like if i buy 2 10% discount cards do i get 10 or 20% discount

you'd only get 10% the cards themselves are only worth their %, they do not stack. THey only stack with the main shop shopping buff. With that you get one % first then the second %

Example an item costs 100 and you have a 25% card and then the 15% buff 100- 25%= 75 75- 15%= 64.5 (if I mathed right lol)

but point is it would not stack together to be 40%, it's like a sale at a shop and getting an extra % discount by using their store card, they work separately

Just a note that the 15% discount buff is removed before your discount card.

ok thank you