Can you just let people prepay a certain amount and deduct from that every month? You don't want to charge 30 cents a month, but I'd happily prepay $10-15 and h

Can you just let people prepay a certain amount and deduct from that every month? You don't want to charge 30 cents a month, but I'd happily prepay $10-15 and have it deducted from the total every month. If the problem is not wanting to support a bunch of small accounts, I totally get that, but if the problem is credit card fees every month, there are lots of ways to avoid that.