Anecdotally, my wife owns a villa in a fifth tier city (even under another city as a prefecture!), and housing prices there seem comparable to a smaller American city (like say Spokane) of similar size.

The median income in Beijing is around 18k RMB/month. The one bedroom we were renting was 7500 RMB/month, which was considered neither cheap nor expensive...it was definitely cheap for what I was making but then I had to forgo a lot of niceties that I wanted (like a real shower). My rent in the states is much higher but I don't have to worry about the same crappiness that even a high-end Beijing apartment has.