Looking for stock photos for Gift Vouchers

I want to start using Gift Vouchers on my website but I want to do it in many varying denominations from $10 through $100. Unfortunately the program only has 3 available and it does not cover all the denominations I want. Is there a place I can get stock photos of gift vouchers to use in ads that would be in varying denominations? I know with some work I can also modify them but I'm not very proficient in PhotoShop and would prefer them to be stock and all of the same design.