For the price, you can get a Nvidia 6200, unlock the pipelines on it, and OC it (if you dont know how, someone will help you) and that will make it as good (if not better) than a 6600. Now, for $100 or less, a 6200 is great with the unlocking and OCing.
get a 6200. NON turbo cache, and 128mb ram. that will be your best buy, trust me.