Put in a search on Ebay. I bought a S&W original 6 months ago, very nice, about $130. I still have the search and there's always a few. Some dogs that keep getting relisted, but you can find one if you read your ebay alerts every morning in your email.
If the one you're looking at needs a barrel, no more than $300! Especially if just a shooter grade.
What's wrong with the barrel? if just a little to moderate pitting, accuracy won't be affected. If it's a sewer pipe or bulged, get a replacement and lower your offer on the gun.