I was in college when the turbo came out.  Babbages, Service Merchandise, EB and TRU were really the only retail outlets locally in SC.  A couple mom and pop rental stores had games as well.  I had about 10 people into turbo just because of showing it off, but it never caught on.  Once NEC stopped the advertisements, availability really went downhill.
My buddy and I would occasionally drive up to Raleigh, NC to check out import games at Buy-Rite (we found out about it through the Turbo List.)  The guy sold things mail order too, but he was a piece of work dealing with over the phone.  His was by far the best selection of stuff, so I assume Raleigh had some market.  We ended up getting Drac, Shubibinman 3, Nexzr, Spriggan, Cho Aniki, Metal Stoker, and a bunch of other great games from him over several years.  He gave us each a hucard converter when we bought our first import hueys.