I have done some research and my research shows that every MMO on the market right now give a free trial period that requires *no* purchase. This is really important to consumers because you need to be able to test the waters before committing to something like a months worth of playtime.
The free trial should be completely free of charge, give a free download to the game, and offer a set period of time or level cap (EVE or WoW, respectively).
Has this been spoken on yet?