I probably wouldn’t pay a monthly subscription (which may very well just mean I’m simply not part of your target audience, and that’s fine) — though if I could use something super simple like Apple Pay to buy a few scans for $1, I would probably do that.
Interesting thank you. It looks like an additional resource-usage model could work in OP's case. Though with financial transaction fees starting at $0.33 of that $1, starting higher at 3-5 might be more appropriate.