Ati's midrange card, the 5770, is about 4870 level performance but its msrp is $159. Seems to be selling above that currently. They also have a 5750 for a msrp of $129 (for the 1GB version, supposedly a 512MB $109 part is due).
Doubt they would come out with a low end part that performs like the 5770 for cheaper considering how new the 5770 is.