Game suggestion for my friend and I

My friend and I are looking for a game on steam to play together. It does not have to be multiplayer but should preferablly be enjoyable to playat the same time(via skype) as my each other. We are looking for a game below £7, any suggestions?

umm if you can find a pair of coupons CS1.6 or CSS are a blast in competitive play another good one i like is space marine but that costs an arm and a leg haha

from the free bin i recommend alien swarm, moonbase alpha, APB: reloaded, tf2

Well we already have CS:S and TF2 and myfriend is not really into starategy games, butwe'll have a look at what you suggested.

LOL seems pretty popular with the crowd

Terraria

LOL seems pretty popular with the crowd

BattleSpectre

ooh you could save up and get sanctum. sanctum is a tower defense fps that focuses on teamwork and co-ordination to get the job done. based in the unreal engine. speaking as an onwer and a person who ahs played the game for longer than 8 hours total. its an absolute blast with a friend. its got bright vibrant locals, challenging enemies, cool toys to play with and a sense of humor to boot

http://www.gamespot.com/sanctum-2011/videos/sanctum-video-review-6312220/

since release there ahs been 3 new free maps and two dlc maps. there has also been 5-6 dlc traps