Curiously, my best deals have come from cities that do not have hardly any used bikes via C/L, and often, from less than affluent areas. Sometimes, affluent areas are full of crap bikes. I know one large affluent neighborhood near me is the land of XMart bikes. I don't get it. People that wouldn't buy shoes for their kids from Walmart, seem to have no problem buying them bikes there.

My two Italian bike pickups this year were both from areas with few to no used bikes, and not exactly affluent.

Of course, I am looking for deals, rather than availability. If I was looking for a great selection, then a city like Chicago would be a good choice.

In my area, Charlotte and Atlanta have large quantities of used bikes for sale. But the deals I have found tended to be in BFE: Newland, NC, Toccoa, GA, LaSalle, IL, Manning, SC, McCausland, IA, to name just a few.