I am not sure about US based, the only two I can think of are OVH and Hetzner and even then I don't think you're going to get something which supports virtualisation for below $50. I think you really will struggle to find something on that tight budget. I think you are going to need to look at around $100 in my opinion but I am prepared to be proved wrong!
What is it needed for? What sort of performance are you looking for?
My suggestions of OVH and Hetzner still stand, I think they are your best options for something cheap. You can get a 4th Gen i7 4770 which is a solid desktop CPU and 32GB of DDR3 ram on Hetzner for €49/mo which whilst is not USA its a very good price. You may have additional costs such as additional RIPE IP's. But I think that is where I would start looking