In my design it's can be expending to online payment integration/ escrow / exchange / portable payment machine(not app, it's physic pos machine, also probably will have ATM machine but need face competitor coinstar competition).
It's nice to see all of those integrated within the processor but when it comes to automated escrows, it'll be hard and tricky to deal with disputes.2 months later once it's online, I may need ask for funds financing activity because need money to promotion.
Not sure if you were planning to offer a 0% fee but if that's the case, then I'd suggest charging a certain fee for all of the payments made through your processor and also sell the white-label type for a certain fee; This way you might no longer have to rely on investors funds for promotion [self-sufficient model].not zero fee but will be very low and probably like you said fixed charging cost.
