I bought my Turbo Duo new from the EB in Midland; Mi, also purchased there; Dungeon Explorer 2, Riot Zone; Sim Earth, Cosmic Fantasy 2, Lords of Thunder, Cockwing f*ck. From the Diehard Game Club in Waterford, Mi; Yuna 2, Startling Odyssey 2, Dragon Ball.
Oh, you mean in the last 10 years? Well, it happens. At the Midwest Gaming Classic there was actually quite a bit of Turbo and PCE. Working CD systems are always a problem, always have been, but basic games are not. Price is the issue. People always say, "I saw Blazing Lazers for $200" or whatever. This is because they wanted to actually have a Turbo thing in their store for a minute. If they charged anything like a reasonable price then it would be gone in seconds. As a store owner those are your choices; charge 8x what it's worth so it will be there, or charge a fair price and see the first customer who walks into your store by it.
There were plenty of Turbo games to go around originally. What happened was that now the power collector is the standard. Everyone who owns a Turbo feels the need, for some f*cking reason, to own every game. They will NEVER play this stuff, they just want to own the "complete" collection before they inevitably dump the whole thing on a new generation of complaining noobs. With every system owner now hoarding 20x as much software as NEC manufactured, scarcity has been artificially made real.