Boards with CFX and/or SLI support usually costs a hefty sum. Here's what I recommend:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131833
I use this board, an mATX packed with features, and I'm satisfied with it.
Hmmm. Question, what would your rig be for? Because there's really no need for a 3770k if you're just gonna game. If that's the case, you could just get a 3570k and invest in a better mobo.
Edit: I saw some sub-$100 boards at Newegg, but they're not Z77 and don't support overclocking