There are still plenty of them around for $20k, more or less!
Friend of mine wanted one, he was serious, and has the flight skills and such.
The problems, as he found out, with the Mig-15, were that the FAA was pretty much set against that particular plane flying in the USA. Very poor build quality, it was a semi-disposeable airplane. The engines have a fifteen hour TBO...they were supposed to send the engine back to the factory for service after only fifteen hours. The factory would strip them down completely, and toss a lot of worn parts, and rework the rest and build new engines out them, something like that. It was not designed to last, it was not designed to be serviced, it was designed to be flown for fifteen hours and then rebuilt in total. That's what my friend found out, and that's why the prices were(and are) still low.
Saw a Mig-21, which is built to a better standard, for $125k.
There are a lot of pretty advanced aircraft out there selling for cheapo prices, like F-100s and Mig-21s and such, but the planes you actually see guys FLYING are stuff like the L-39, planes that are built to a high standard, and that they can actually afford to fuel and maintain. Sabres, you see a bunch of them, too. And Hunters. But my guess is that the number of airframes around greatly exceeds the number of guys who can actually afford to fly them, and have the skills to fly them, so that's why you see Bonanzas often selling for more than jet fighters!