It looks like a pretty good start. I'd probably pick up 4x Mana Leak and replace some of the more clunky counter spells with those.
I'd also probably cut a couple clones and add in a bigger killy creature of your own, but I guess if you're looking to keep costs down you're fine.
There's a bunch of cards you could toy around with in the 2-20 dollar range, but that adds up quick.