I have a 20% off discount card and I keep getting the 15% off buff and I cannot figure how to turn the 15% off. I'm coming back after a long long hiatus. haha Thanks in advance.

The text will look something like this:

The bold is the line that mentions your discount card. The italics mentions your discount buff. The discounts come off one after the other so if you do the math for both discounts, it should work out to be whatever the number is on the top line. (In my example, 497 x 0.8 x 0.85 gives a final price of 337.96, rounded up to 338 which is what I paid)

... wait, so the 15% buff does combine with the discount card??

lets try this.

Shop price: 1504sP I see you have a discount card! I'll give you a discounted price of 895 sP! How to Build Sand Castles has been added to your inventory. Your main shop discount buff gave you 15% (226 sP) off the main price!

(that´s 1504sP x 0.7 for my 30% discount card (so that would be 1052sP), x0,85 for the buff) = 894.88sP

Yay, after all these years with my discount card I finally figured that out. Thank you :D

the buffs can wear off on their own i get buffs at most times