I guess that is how they make their living. And unsuspecting family are happy to get a few quid for grandpa's old "junk".
Myford Super 7s are worth quite a bit these days, especially in good nick. I think you can look at past sales on eBay to get an idea, and various classifieds on this site and similar, and I think homeworkshop.org.uk. They seem to bring quite a bit more than the standard ML7.
And the accessories and tooling can add up to as much again, depending on what you have. Thing is classifying, advertising, packing and sending myriad small items take much time and effort. So might be worth setting up a package to sell as one lot with the lathe. Usual kit that goes with a lathe is the set of change gears, a four jaw chuck as well as the three jaw, fixed steady, travelling steady, tailstock chuck and tailstock centre. But y ou could add more and up the price a bit with milling slides etc etc.