Strategy game Great Big War Game, the sequel to Great Little War Game, has a kind of Advance Wars (Game Boy Advance, DS) thing going on, and I dig that. It features turn-based strategy, but with a cartoony style to make warring a bit less heavy and a bit more fun.
You get a ton of game for your suggested $9.99. Great Big War Game has 50 single-player missions in one big campaign, and 30 unit types to play with. There's asynchronous and cross-platform support for online play, and over 70 multiplayer maps to battle it out on. Someone needs to do the math on gameplay per dollar for this game.
Great Big War Game is now out for PC (retail) and on Steam.