Is it possible to use coupons when using ccBill for the payment processor. I know they have a loyalty discount, but I don't believe it is the same as the coupon.
No, unfortunately, it is impossible with aMember, because prices are hard-coded in ccBill acount seetings and aMember cannot pass variable price.
Is ccbill the only integrated vendor that will not work with aMember coupons? I'm interested in maybe signing up with other merchants so that I may use aMember's coupons. I just need to know which payment processors aMember can use it's coupons with. Is there a list?
Unfortunately, there is no list. There is no much payment processors that supports adult sites, to be honest. However, if coupon discounts can be somehow defined on ccbill side, it will work.