That lathe was made by Atlas for Sears and is usually referred to as an Atlas 618. This one doesn't come with a quick change gear box, but the change gears do look like they are there with the accessories, which is good. From the first photo it looks like the handle for the cross-feed screw is broken. This can happen any number of ways. More often than not it occurs when the lathe is dropped. Take a close look and make sure nothing is bent. Also check for slop in the cross-slide and apron. Run the carriage the full length of the bed to see if it binds anywhere. They tend to move smoothly and have more slop close to the chuck where they are most frequently used, but further away toward the tail stock end it might be a little tighter. Some amount of wear is expected; excessive amounts are not. Chuck up a piece of rod and see if it turns relatively true. With the motor in the off position (and you said there isn't a motor anyway) lightly lift up on the rod and see if you feel any movement from the chuck and spindle. This could indicate wear in the bushings. Lift the covers and look at the gear teeth. Are any gears broken/missing? Replacement gears can cost $10 - $40 each on ebay if you need to replace any of them. I don't see the jack shaft assembly with it, but those are often missing. The $500 price tag looks like it is in the neighborhood for what it is if it came with the jackshaft assembly. And that assumes you don't see any red flags. I'd offer him $400 and see what he says if you really want it.
This is a good lathe to learn on, but you will probably outgrow it before too long. If you can find a 10" Logan lathe, that would be money well spent. They are well designed, have tapered roller bearings instead of bushings in the headstock, often can be found with a LOT of accessories, and are easy to break down and transport. I just picked up one myself that was for sale locally. It completely fit in the trunk of my Camry, was fully tooled, and I bought it for $300.
Maui
