Tying in with Tesh's Ratcheted Subscription, I have just one suggestion in terms of subscriptions. Simply one of paying a set amount. Say for imagine, five hundred dollars. You pay your fifteen dollars a month as usual, but once your monthy fee has gotten to five hundred, you don't pay any more.
The idea is the company puts aside some of the money into bank accounts and accrues interest, which pays for costs and makes profits. So in this subscription type, your kind of investing into the game.
Of course, why do that if you can keep bleeding people each month AND all the people your bleeding can't imagine it any other way? No logical reason at all, really.