They come up on Ebay frequently, however like Don said a good one is going to be expensive I've seen really nice ones on Ebay go for $800+.
Thing is, they are well made machines, and well made machines that don't look that good usually sell for alot less and respond well to being taken apart and cleaned and reassembled.
Every loading machine I have has been completely aprart down to the last screw. All the parts get a trip to the wire wheel or scotchbrite wheel, and repainted or blued as needed. You end up with a new machine that way, and you also learn the inner workings of the machine.
Here is a pic of my $150 Pacific 366 which sat on some guys garage floor in the corner for 20+ years. It took 4 hours to make it look like this. Oh, I had to replace the shell plate and the little plastic doodad on the primer drop. I think I spent $12 total. It even had the right powder and shot bushings already installed.
Here's a pic of my C&H AutoChamp It needed no parts and cleaned up to what you see here from a complete turd.
Good machinery doesn't usually wear out and if it does then with a few parts you can make it new again. ANY Star loading machine falls into this category. Unless its been dropped or knocked off a bench repeatedly it will come back to new with just a good cleaning and maybe a few parts.