Some good options in this Summer 2015 Steam Sale and there will be quite a few more over the next week. In the meantime though I've come across a game that is quite fun and also cheap!)
It has online play and it's like a frantic competitive race with combat in the style of the classic prince of persia game. There is a singleplayer challenge and plenty of options for local play including a tournament mode. There's also a 2-pack option available if you want to buy it and play it with a buddy. £1.09 is a fantastic price for an acclaimed game.
Here's TotalBiscuit playing it!