[Asmodai]

Have a look at SWGEmu (easily googleable), a community project to build a free to play emu of pre combat upgrade era Star Wars Galaxies.

The current server (test centre: Nova) is the only server and it's in a late alpha/early beta stage (still plenty of bugs), but you can play the old Star Wars Galaxies in most of it's glory for free if you've got a copy of the discs or can get them.

Runes of Magic is also decent, it's a WoW-ish free play based on diamonds (ie. microtransactions). You can play entirely free, trading gold you earn in game for rented mounts etc and crafting stuff for yourself, or buy diamonds and buy thigns like perm mounts and crafting stations for your house.

It's pretty straight forward and fun. I only bought diamonds once and spent what I'd spend on WoW over 2 months play. Played for 6 months free so I reckon I got a decent deal (there is no initial cost to play so for the cost of buying a boxed game you can set up one toon very well if you do choose to buy diamonds). The downside is the economy is hosed and anything of value sells for diamonds now. A diamond went from being worth ~5k gold to 50-60k last time I checked (months ago now). I don't imagine the inflation got any better.

The rest is a mixed bag, but they are free (apart from the download quota you have to use to get them), try em out and find out what you like I guess. =)