I'd have to say for me. I was trying to go by account worth, but it's so inaccurate, and didn't even show some items I own. But the bow was 375 mil when I bought it. And that doesn't begin to cover the rest of my battle set, although I was lucky enough to earn most of it myself.
Apparently 1x: DSLR Camera @ 50,000,000 sP c: (though honestly it's currently worth like 9mil pft)
Bale Hair Coupon @ 34,915,165 sP Says my account worth~ <3
Ha! Mine is just the Tempest Lightning Rod. Needless to say, I don't have a very impressive account worth. lol

1x: DSLR Camera @ 50,000,000 sP 1x: Decadent Strawberry Blondie Cake @ 50,000,000 sP 1x: Creme Eyeliner Pot @ 49,989,999 sP
are my top 3
• • •
This thing: @ 15,384,579 sP; which I'm actually trying to sell for less than that >_>

Mine is , considering I paid 465M for it.
is second, with it being sold in the MC for 400M.
My Battling Tumblr
Buying discounted Kumos items and intelligence boosters.
Comment/sMail me if selling.
Mine is a Cursed Pearl @ 17,160,000 sP
I don't know if I paid that much, it was a long time ago. xD
1x: Shrug-Wearing Mole Plushie @ 8,018,000 sP
Not too expensive, compared to all of your items! I'm not too much of a big spender, and I can't remember how I got this.
❄️ Seeking Elsa or Olaf inspired CWs ❄️
with eight priceless items found...
1x: Kahaleitzli Bobblehead @ 50,000,000 sP
[tot=ravenclaw] 🎃
1x: Creme Eyeliner Pot @ 49,989,999 sP
with 130 items unpriced xD
Status: Offline
[/font]My most expensive item is probably the hair I'm wearing right now. XD . I do so love them, though. :)
Empty Champagne Bottle - 44M Mushroom Ruffled Blazer - 28M
I think this two are the most expensive items.
Prodigy Staff @ 50,000,000 sP
According to the account worth page :P but I think the most expensive thing I own is
Viv Muggy Oxfords @ 19,978,000 sP, apparently c: