Looking for a decent free MMO

Star Wars Old Republic not bad but a little grindy in parts when playing another class of the same faction (grindy with rest of the planet you have to repeat). Star Trek Online or Champions Online fun if you like those. For a small amount of money, Guild Wars2 is an mmo where they do small story updates every few weeks & once you buy the game that's all you need (no subscription).

TERA, Raiderz, Aura Kingdom, Lineage II, Rift.

Anarchy Online, oldie but goldie :)

RIFT is great on steam (specially their concept of "free" is really good, no gamebreaking limitations/annoyances)
TOR Online is pretty sweet too if you like real interaction with storylines, and star wars. (but their free version is more limiting, also nonsteam)

• Dark Fantasy - Rift
• SF - Defiance

Maplestory LOL but srsly (unless ur a MS type then more the merrier) All the Nexon titles are pretty fun; Vindictus and DragonNest, as well as Mabinogi if you like to take things slow.

rift

The Secret World

I'm also wondering if I should splurge and buy Wildstar or TESO. Are they any good? Wildstar seems to be a mix between Rift and WoW. I like How TESO looks but will it become boring after a while? How is the combat?

I'm seeing a lot of older titles here.
ToP is still fun to play, assuming people still play it.
Zu Online was pretty unique-ish for its time, and I'm pretty sure people still play it.
KO was pretty fun, not sure if it's still relevant.
Maplestory is, technically, still relevant but not exactly good. If you can find a private server, go for it.

Those are ones that stand out in my head right now.

People here have suggested a lot of good MMOs but there are a few choices that would be bad for a F2P player to pick up, if you want the free part.
LOTRO and SWTOR are both horrible at providing a free game. Both limit you in such ways that game play becomes more infuriating than fun.
SWTOR gives free players a limit on weekly pvp battles. LOTRO wants to sell you dungeons and quest hubs. In both games you are constantly reminded that you're a free player and that you need to buy your way in their worlds.

There are some good Everquest-based MMOs out there that are truly free. You just have to fiddle with the EQ install to point to unofficial servers and patch in custom content.

You can also go old-school and play some of the original MMOs: MUDs. Aardwolf is a good one.

Then there are the MMOs that are a little different. I would recommend Kingdom of Loathing to just about anyone.

there's no such thing as free mmo really, one way or another you have to pay.
But if you mean f2p(free in theory), i'll say DDO.

BF Heros? maybe?

I personally enjoyed Dragon Nest very much.
I tend to play through most MMOs alone, unless I run into trouble on a very difficult mega boss or something.

Spiral Knights. Not very popular but fun and interesting.

After playing wow for way too many years i didnt find any mmo wich could satisfy my taste in mmo's even eso nor wildstar in terms of free mmo's i enjoyed Path of Exile the most that one i could recommend but keep in mind this is just an Opinion of a former biased wow player. Geuss i am one of those few who are mmo ''tired'' or burned out from mmo's lol

Age of Wulin is a free-to-play martial arts MMORPG (Massively Multiplayer Online Role-Playing Game) set in a charmingly realistic representation of medieval China; with 18 “scenes” representing all geographical regions of the country - all presented with stunning graphics.

Thousands of quests, vast and diverse regions to explore, and over a dozen challenging instances make Age of Wulin one of the most expansive and ambitious free-to-play MMORPGs to date.

http://en.wulin.webzen.com/

Could wait for archeage online

Defiance

dude, invest some money and buy Guild Wars 2 (no monthly fees) game is alive and well

Cabal Online has a unique combo mechanics and game design, but nowadays only worth to play on private servers.

RIFT! RIFT! RIFT!

Scarlet Blade !

Really? No one mentioned EverQuest 2? Slightly surprised, seeing as even though it's an old game it still has a relatively large playerbase and almost no P2W aspects as far as I know.

I played Aion for a while a year or so ago, had a BLAST, and it wasn't p2w, like a lot of games out there.