power steering to manual sticker shock

It's been my experience that the manual boxes rarely wear out or leak. I'm not saying it never happens, but I've never seen one that couldn't be adjusted if it was a little loose. Now getting bad rebuilds (carbs, alternators, water pumps, you name it) is pretty common. With that in mind I think you've got the same chances of getting a good used one as getting a good rebuilt one unless you're going to a well known and reputable company. If you do, they're not going to be cheap.