Its 1/2 inch drive. I don't think has much value as a working tool more of a collectors item.
Why not? It's hard to find speed handles with a free turning center handle nowadays. I love my old Craftsman speed handles because they have this. The down side is I'd prefer chrome.
As for price, well, I see one just like it on Craigslist for $30.
Hey, it's in the same town as you too.
I don't know the collector value myself. As a working tool (if I didn't already own two nice chrome Craftsman speeders), I'd probably pay $5-10 at the flea market for this. Being that it isn't chrome, I don't think I'd pay more, but as said above, if someone is looking to fill/match an old tool set, perhaps they would.