There are a lot of online multiplayer games on the internet that are free of charge. I suggest gamehouse and addictinggames. Those are the sites that I use most often.
Aeriagames.com and also outspark.com
Some good midieval games are... Fate (19.95) Fate Undiscovered Realms (19.95) Runescape (free online multiplayer) World of Warcraft (free 14 day trial also an online multiplayer) Wizards 101 (free online multiplayer)
Here is a short list of good multiplayer games:runescapewizard 101clubpenguinspineworldbinweevelshabbo hotelguild warsThere is also a link in related links to a site that has a list of free online multiplayer games.
Mara pets is FREE, Fun, and no download!!! Just follow the link below!! Also Cosmictopia.com is good place to play online games also multiplayer games.. You can play free at yepi2.co and yepi-juegos.com
MAG
wizard 101 kids and adults can play this 3D multiplayer game
minecraft is the best answer you can play free at minecraft.net you can also buy the game and get more from it but other then that minecraft is the best answer all the rest like manic digger are just copy's of minecraft and are not that good minecraft is the best one minecraft is online multiplayer its even multiplayer on free version
i have a ps3 in my opion multiplayer games are off this planet
There are several sites online that provide free games. Try freeonlinegames.com has a very extensive collection of games that can be played online or downloaded to your computer for free.
If you like Pokemon Pokemon indigo,wizard101,andfor some non online fun go to addicting games
The PS3 does have some 2 player games that are great without requiring online multiplayer, but most games are single player and require an online connection for the multiplayer.
There are many good free online hunting games like Seal Hunter or Marksman Hunter. One can find good hunting games at places like Newgrounds, Kongregate, or Tremor Games.