HyperSparcs are the processors that were in Sparc 20s. (Sort of. There were also, originally, SuperSparcs, but they were more complex, and, as it turned out, ultimately slower. I don't really quite understand the ``run'' comment, either.) If you see it specified that way on eBay, it's likely to just be a processor with no computer around it.

I don't know how much money you've got to spend, but the best buy in the Sparc arena right now is probably the Ultra2. You can get one for a few hundred dollars, it's not that many revisions back, and can be upgraded quite a ways.