Blood and Bacon. well, that game is FPS, but its cheap & very funny game.
or try Party Jousting. its F2P games

Well if you wanna try a fps without the other guy, Blood and Bacon looks fun !.

Golf With Your Friends (5.99$) A pretty fun mini-golf game to play with friends.
It's still in early access though and the price tag may be a little bit too high. It's just a matter of checking some gameplay and see if it pleases you.

Out of all the free games that people already recommended, maybe try Trove, I never played it but a friend of mine did and he said it was really good

You can also browse through all the free games on steam yourself.

Bump, but no good suggestions, sorry. I typically play solo. :(

Phantasy Star Online 2! it's not in steam though

Maybe this could help you: co-optimus

another vote for Warframe here, but its archwing mode is known to cause motion sickness on people that are prone to have it. archwing mode plays a really small part on the game and is (almost) completelly avoidable though.

torchlight 2 gets really cheap on sales and is a good option if you guys are into some casual arpg. also on the casual side are Yet Another Zombie Defense, Nation Red and Hammerwatch from which i have quite a lot of fun with some friends now and then. they also get very cheap on sales.

if you're into some racing, give DiRT Showdown a try. (also wait for the sales).

and thanks for the gib :D

Dungeons & Dragons: Chronicles of Mystara Not sure if there's online function in this game, might have to ask around first
and
Worm games, like this
Torchlight 2 is good too, but it's not cheap at the moment
or newest Rayman game.. Cheaper one

I don't know about you but I like retro games, people these days seems don't really like it

CHIVALRY! lol only downside is easy to team kill also Killing Floor was bundled before goes on sale allot ;)

I can't think of something else than what you have, but here's a bump. :)

I don't know who said Terraria, but that game is incredible, and can easily give your group 50+ hours of awesome play.

A lot of games in that list are good, such as Golf with Friends, Bacon and Blood or Castle Crashers, but I feel like you'll only get like ~5 hours of fun play for most cheap coop games.

Terraria is in a world of its own, what a game:)

thanks for updating the OP!

Blazerush

Friendlessbump

Warframe could be fun for your group, yeah, but as others have said, it probably won't be great for that one friend of yours. Also, it tends to be somewhat... fast-paced.

orion- prelude has the option for third person i think?

price $1

havent installed it atm other wise i would check it for the third person part

DOTA 2? but it's too toxic :|

One of your best bets to find some good-quality cooperative games would be to pay attention to https://www.humblebundle.com. Check in once a week or so and every couple of months you'll likely find $1 or $6 bundles that have cooperative games in them. There have been quite a few multiplayer / cooperative indies over the last couple of years. Of course this is subject to being at the right place at the right time. And once you do find a game that you think you and your friends might like, be sure to check out https://isthereanydeal.com/ to see if its on sale anywhere or currently in a bundle. Sometimes you can save yourself some time/money that way.

http://store.steampowered.com/app/99900/
Spiral Knights is free on Steam and supports up to 4 players in a party. If you play it more like a challenging action game (light brawler) rather than thinking of it as an RPG you'll probably enjoy it a bit more. Supports multiple levels of difficulty and all progression is tied to the items you own so if you play more than your friends, you can still down-equip back to their level if you wish. Upgrading gear can be a bit of a grind, especially now that the economy has fallen apart with the lack of influx of new players, but if you enjoy the cooperative action-element of it, you probably cant go too wrong giving it a try.

http://store.steampowered.com/app/113020/
Monaco (Bundled a handful of times, 4 packs often go on deep sale during holidays.) is a casual if somewhat chaotic top-down stealth/heist game of sorts. Depending on the number of players in the game (1-4) it can be either quite simple and straight forward, or just plain crazy with traps going off everywhere and rescues needing to be performed. It feels like its more of a party game than a single player game but has multiple characters with different skills / playstyles and is largely focused around doing the heist as fast and efficiently as possible due to the way its scored. Is a fairly simple one-button stealth game, but if you like to chase high scores by yourself or with a group then theres a bit more replayability here.

Whoa, i have a friend that get dizzy easily when playing fps too!
Might want to remember this thread for future references lol :p

Just droppin' by to add a ticket to the Guild Wars 2 box. Amazing game, I wish I had three friends to play it with. Try it for free and upgrade to full game if you love it, it's definitely very relaxing, not competitive at all (unless you join PvP), huge amount of content, no monthly fees, no pay2win, being updated very often and has very nice community. +1 to Terraria, Hammerwatch as well.

Trove maybe? http://steamcommunity.com/app/304050

Dungeon Fighter Online is an MMo not a competitive game unless you go to pvp majority of gameplay is in dungeons either solo or with up to 3 others.