That one looks to be in better shape than most... but I wouldn't invest $500 in a ShopSmith. Most likely you'll never use the horizontal boring, lathe, or disc sander. Which means you're paying $500 for a drill press and a tablesaw that has less capacity than a modern benchtop saw.
IMHO, you'd be better of buying a circular saw, a top-of-the-line blade, making a sawboard, and buying a bench-top drill press. Throw in a pair of saw horses (I like the
Stanley Folding Adjustable Saw Horse Twin Pack for $55) and a sacrificial sheet of 3/4" plywood to make a huge, yet collapsible, cutting table. From there, you just need a few decent measuring tools: a
FastCap Flatback tape measure, and a
Starrett combination square and you're good to go! All for less than the ShopSmith...