You can automate an ebay search
You can automate an ebay search, set up a radius (in miles) from your zip code, a price range, a name brand, etc.
Let's say you wanted to search on either Sheldon (R15), or Harrison (M300), or some other machine with metric and standard threads from the quick-change, your search terms would be
(Sheldon, Harrison, Andrychow) lathe
You need to determine the spindle bore you need, the headstock length you can tolerate, the electrical you can supply (single or 3 phase, at what voltages), etc. You need to determine the swing desired, the center to center desired, the sort of chuck system desired, etc., otherwise you won't be able to narrow down your choices.
And how far you can drive, how much you can spend.
Ebay will send you an email each time a matching item is listed. The 'save this search' checkbox shows up when you do an "advanced search".
Good Luck, and start asking around town if anyone has a lathe they would like to sell. Take notes on the make, model, condition, etc and come back to P.M. and ask for its reputation.