Most of the salvage yards will sale the wheels for 150-185 each because that is about what scrap price is for the wheels.
Trust me it is a whole lot easier to buy new than to mess with the used wheels. When I first started milling these wheels used was all I did. I would get 4 out of 10 wheels that were unuseable. Cracks and egg-shaped wheels are the ones that will bite you in the ass with used wheels because most of the places you buy them will not take them back because they were going to scrap anyways.