Forcing users to OVERPAY for apps....

All I want to do is purchase an APP here for $49, which is it's listed price, and I am willing to pay it. Unfortunately the vendor (AQB) seems to only take credits for the purchase. The issue here is that although credits/Money is a 1:1 ratio, I cannot purchase 49 credits directly; I am forced to buy 60 credits (For a real total of $60 USD) just to buy the APP for 49 Credits. This means that UNA itself is gaining a profit of $11 for no reason at all. I don't have issue with UNA making a profit (Afterall it IS a business), but I feel kinda scammed when I am forced to overspend just to make a single purchase...