On the low end one would expect to get about $150 for it at the scrap yard. If it is running and in usable condition, at least $1000.
On the high end if it is really nice, clean, pristine and accurate, it might bring $5000 or more. Add more if there is a four jaw chuck,
a nice tool post and holders and a bunch of tooling...
I have an old war years 1942 Monarch 14C(16x33) that I paid $1500 for about 15 years ago. It came with a 3 jaw chuck and a big old
home made tool post and some HSS cutting tools. I would say it was in fair condition when I bought it and would call it good condition now.
One of the main reasons I bought it was because the owner offered to deliver the lathe to my shop. I have no regrets.
That said, the worth of any lathe is what someone is willing to pay for it.