I got mine last time it was made available in the Millionaire Center, and I think it was worth it. If you like to make sP out of restocking, you'll probably find this a good item to own in the long run. 
Mallowwater - if you're against the discount card, fine... but I don't see why you're trying to talk everyone out of it.
Yes, it is true if you only buy items that are 500sp or cheaper that it's going to take a long time to recoup your 15 mil... however, if you buy items that are priced in shop in the 100k range, then each time you do so you save around 30k - after 500 purchases your discount card is paid for, and for the better restockers who can typically restock between 1 and 4 of those 100k items per day, you've paid for it in only a few months with the money you've saved.
It doesn't take long to make it back, and for those who are die-hard restockers the cards come in VERY useful...
thats not so bad.
Total Sales: 467 Total Profits: 5,008,246 sP
-blah- I think I will pass on this one xD. would take me 9 weeks to break even on it...ROFL...wait o_O...but everyone else is quoting longer o_O. maybe this may be worth it sigh -confused- will have to think.
its also for those 100k-200k restockes in weapon you save like 30k-60k each time you restocker something that expensive
crap, I'm 4 mill short!
Yea but if you're saving money with this, by the time it goes out of the shop, you've made some money off it already through the shops, and you can sell the card again. 
2GodBtheGlory - I'm going to paste here a part of the message i sent to Paintinglies:
I think that people fail to see that yes it is very possible to earn a million a day through restocking but no it's not because of that discount. The discount only lessens your expenditure by the amount that is irrelevant given the item's selling price. People are mislead thinking that selling a bargain for a lot of money has made the trouble worth while: you make the profit out of selling anyway. If you pay 70 sp instead of 100 sp for a cheap plushie and sell it for 19000 sp you still have made the profit you would initially have - the only thing is you have saved your 30 sp. The thing is, these 30 sp will have to be repeated lots and lots of times to reach the infamous 15 mil.
It is out of all these 30 sps put together in the to-pay-off-the-discount-card fund that you are trying to make up for the invested 15 mil, and not out of the high rarity items you are aiming for to sell. That is why it is so pointless. Can you see my point?
x______X So expensive.. I only have 6 million at the moment.
Urg.. I bought one. Losing 15 mill made me feel sick, and now I'm down to 5 mill. siiiigh I just gotta keep telling myself that it's worth it... down the road...
I need to come up with 15 mill before they take it away again 
price bump = not a bad thing. afterall back when it was 3.5 the average subeta user had 15k, when it returned at 5 million the average user had 55k, now the average user has over 670ksP so 15mil seems perfectly fine for the card.
How long does the card last for?
Well I just bought one. I've been waiting for it for a long time. For me it's a good investment even though I don't RS every day. 1) I plan to stay with Subeta for a long time and I'll be able to use this forever and ever and 2) it makes an awesome collector's item just in case I ever want to sell in the distant future.
And I love getting discounts on my purchases.
I think I'll buy one off somebody once I get to 70mill... And I thought I could buy anything with 20mill, but that's just too much... Grr.
Thanks, Mallowwater, for explaining this item. I am holding off on buying one.
I'm selling mine for 14,5 mil
It all depends on how good a restocker you are! 
Actually, I can buy several items in one day for 300 sP or less, and sell each one for 4-10k+... I can make 2 mil per day (and I've done it before), would this be a good investment for me? ^^;;
Of course, that is assuming you aim for all the cheap items. Skilled restockers can take the initial shock to their wallet and with a handful of high rarity items restocked (also taking the current high levels of inflation for said items) the earning power bursts exponentially. It's all in how you look at it. Personally, I aim for higher rarity items. :3 There's a tool for teaching yourself that on DB.
After reading 's breakdown there is just no way I can justify blowing 15mil on that thing. Good thing I didn't purchase it the second it was released, I'd be kicking myself now if I had =
And even then, you don't make a profit, you are on ground zero lol
A restocker who buys approx. 100 items a day from shops, at the approx. price of 500 sp per item, invests 50 k in that day's restocking, which is 1.5 mil in a month, or 18 mil in a year. With the 30% discount the average cipher will drop to 350 sp per bought item, making the daily restock expenditure 35 k, which is 1.05 mil a month, or 12.6 mil a year. Thus, a restocker who buys 100 items a day in average, priced at 500 sp in average, using the discount card will save 5.4 mil a year.
Logic comands: NO WAY it is worth it. It will probably pay off after months and months of restocking, but i wouldn't call that a profit?? To be more exact, it will take one just under 3 years to make up for the purchase of the 30% discount card, unless one is a restocking machine in which case if 200 items a day are restocked you will be able to do it in 2 years time, or in 'only' a year if you restock 300 items EVERY DAY. A slow rate income like that can never compensate for the loss of 15 million in a single purchase.
You've Purchased:
30 Percent Discount Card for 15,000,000
Thanks for your business!
I've been moaning for it's return for months
hmm, I bought one, and guess I'll put my 20% discount card into trades.
I paid $30 for it from cash shop
If you do the math, you will have to spend 50 mil in the shops before you break even. Unless you restock 24/7, you would do better with the 15 mil in the bank.
Haha! Same here =p I'm like, I'll save these items and resell them 2 years to get huge profits. But then I'm like, dang... 2 years is so long! sells now lol XD This card set me back 15 mil from my God Weapon. Meh.
Well, I realize that too, but frankly, I'm impatient. XD
I'm buying it just for the memories of the card XD The profit is bonus. And anyways, the card is forever lol. So as long as you restock and don't quit, then you will make profit in the end.
Well, you misunderstood me a bit, but nevertheless. I can do quite a bit of restocking. I also spend at a phenominal rate, which is why I've made over a hundred million in sales, yet I never seem to have over five million. However, I don't spend a lot on the items themselves. That's why I wouldn't generate much in what I save compared to the normal profit I make. I think I'd rather just have the 15mil.
I probably won't bother buying it then. Thanks a lot for the info, you just saved my 15 mil.
What Illucoran said, the cost is not worth the amount I'd save, even in the long run.
No, this doesn't give you training discounts, but having a GA gives you 15% off training costs. The ONLY thing the DC works for is buying things out of the Official Main Shops, like Book Nook and Toy Box and Subetique, etc.
Oh, I agree, Sky! If you don't do much with RSing, don't invest such a huge amount. This is just a way to make the wealthy invest 15 or 20mil on the hopes that they'll make it back. Also, once it retires from the MC, you could sell it for at least what you paid for it, if you started using it and decided that it's not worth it for your particular situation/buying habits. Also: PLEASE do not spend your last sP on something like this - then you won't have much for RSing OR Quests or anything, really. Don't leave yourself broke; only buy it if you feel you can afford to invest 15mil on something that could take months or a year or more to make a definite return on!
I'll pass, so far I only restock items that got at 1000 or below and it took me half a year to get my restocking royalty counter to 1000 it would take like a couple years for it to pay for itself...
I'm guessing the discount doesn't apply to training courses for your pet. Or I'm I wrong?
Considering that I make most of my money off of items costing 1000 or less that sell for at least ten, if not twenty or more times that, and with what I'm capable of turning out in a day if I try, I'd barely notice the savings. It's not for all RSers unless you want to spend all of your time worrying about your savings.
It wouldn't make sense for it to cost 5mil like it used to - that was well over a year ago, sP was worth more because it was harder to make. It took a LONG time to get 5mil saved up. A 1 Month GA cost 55k, no joke. They went to 100k and people freaked! Back then, I sold a Micracle Potion II for 1.3mil - which was a huge, huge, HUGE amount back then. A vast fortune, one of the most expensive Potions out there. Compared to the inflation rate, and how easy it is for a newbie to amass several million sP, these DC's should actually be more like 30mil or more. Seriously.
If you don't know whether to buy or not, ask yourself this: Do you RS? If so, you need a DC, the savings really add up, fast! On an item selling for 10k, you'd offer 8500, and watch almost 3000 come off the final price. Instant savings of over 4k!
If you don't RS, don't buy one - it would take you years to make back your investment. But for us RSers, it's worth every single sP we spent!
It will take you a long time to get 15 mil out of interest alone. I know for a fact because at 5% interest a day I'm making about 60k a day being richest sp user currently.
Yes, they only work in main subeta shops. Not the millionare center etc.
Even if it doesn't pay off that quickly, it's still a fun item to have
You'd have to restock 24/7 - and if you restock that much to make this pay off, you make enough profit with your sales, anyway. I fail to see the use of such a huge investment - rather collect dayly interest for 15 mio, lol.
Do the shops still grant the normal 15 % from the 30% reduced price?
Does it only work on main subeta shops?
Those on the fence, I will tell you, that sp will be earned right bac ... quickly !
Anyone who intends to make their main profit from restocking should own this item.
Nuff said.
BGG you are really swaying me... and I checked and I have RSEd just over 10,000 items since I've started playing, LOL... all the waiting I've done for this and now to be so uncertain, arghhhh
Eh, I think I'll take my chances.
I think it should only cost 5 mill like the old days
ARGH! I just bought one for 20 million and lost 5 million!!! 
I guess that's my bad luck.....
Ach, I've been convinced. Thanks, Bluegreengrey :3 I guess I could always sell it again if I was unsatisfied with it.
Yes, you have a point there, OnceUponaThyme
People who shop at Subeatique for example are indeed better off with a card like that! And ow - no i wasn't trying to talk anyone off buying the card, i appologize if my post has come accross as if i was! I was just doing some math but only took into account average restocking habits and didn't want to offend anyone who really wanted and bought, and finally profited by this card 
Indeed, kudos to those who have mastered the trade - no pun intended ;°)