So I've got a thought experiment for you guys (partially because I have a small stake in it, even if I probably won't go back to that project for a while).
How DO you fund a truly MMO-based game like this, if not by a monthly fee? I mean, what on earth do you charge for? Pay-to-win sucks, and "you only buy it once" is a great way to bring down the game's servers in a real hurry once new players stop signing up.
Let's be generous and say that an average player uses $0.50 per month in bandwidth and amortized CPU costs, and that advertising costs and pay for the devs are fairly minimal. What kind of payment scheme can you use, which guarantees an average income of like $6.00 per player per year?
For a generic MMO, some ideas for what could be sold are below. Obviously the specifics would change depending on the type of game.
Cosmetic items.
Items that are available to be purchased from in-game shops with in-game currency or that are common drops.
Character editing items, ie name change, gender/appearance change, total reset and rebuild, etc.
Character upgrades such as extra bank slots/inventory slots as long as such slots can also be purchased with in-game money(even if a substantial ammount).
XP boosts if PvP is by similar player level or game is primarily PvE.
Guild/gang/outfit creation charters.
Stuff that should
not be sold in cash shops;
High level equipment with lower level requirements than what can be obtained in game.
Crafting materials.
Items that duplicate those that can be crafted by players.
Items with actual game effects that cannot be obtained in game.
Rare drop items.
Stuff that could be offered to subscribers
Priority login on busy servers.
Longer idle period before being kicked.
Priority tech support, though free players should not be ignored/told to just read the support forum.
Small free monthly amount of cash shop currency.
Free Guild/Gang/Outfit creation.
For subs offering both monhtly and yearly subscriptions would probably be bast, some people prefer either option either because they want to avoid the hassle of monthly subs or only wanting to pay for the months that they are going to be playing.