AdventureQuest Worlds: Web Browser Massively Multiplayer Game Used to have the same problem.
A couple of the servers only have, "canned chat", but I'm pretty sure the majority actually allow you to type in what you want to say.
And there are alot of things (items, quests, etc.) that you can miss out on without donating, but it is in fact, free, and quite fun.
Best part is that there is NO download required.