I got mine for around $100. So from my perspective, and many people who did get it on the cheap, I'm looking at $150 cards and up.

Even the GTX460 is not a compelling upgrade path for a 4850. I seriously debated it for a while, but I decided to wait for the next gen from either company.

Also, from my limited memory the GTS250 and the 4850 were quite similar in performance.