Agree with Iwana.
The lathe looks complete and un-abused, except for how it is stored. It has a motor and is probably plug 'n play after cleaning the ways and oiling.
If there are no broken gears or major parts, if the spindle can still be adjusted with shim removal (not wallered out oval) it is easily worth $500 as it sets. Don't tip it over or break anything getting it out of there.
As far as "restoration" - on a machine tool that would mean rebuilding all the major assemblies to factory spec ("blue printing"), a complete regrind and or rescrape of all the ways, and then possibly replacement of leadscrews. So the answer to that question is "probably not". You could spend the same effort on a more modern lathe with better resale value. Though in either case you will never get the value expended in "restoring" most common lathes or even 50% back. But it can be worth it to your own purposes.
"Restoration" in the machine tool sense does not mean painting. If that's what you mean, sure, slap another coat of paint on it and feel good. Does not improve anything functional, though.
Clean well and refurbish with new felts & the proper oils in the right places will help.
It sounds like you might be a beginner. If the machine is not plug & play after a thorough clean, oil, and adjustment, you probably don't want to start with it at any cost. If anything is broken, your time or the cost to have parts made or sourced will probably put the total cost over what the machine is worth, or create a project you might never finish.
You may have to assess what kind of work you plan to do. Older lathes have slower speeds, which is fine if you do largish work. if all your work is mostly under 3/4" bar, you probably want some speeds abouve 1200 rpm. If you do a lot of bar work around 1" to 1-1'2", you might want a spindle hole big enough to accomodate bars in that range. etc.
If complete, unbroken & suitable to the work intended, I'd look it over a few times, poke at the rust a bit, shake my head regretfully, and offer $350. If that was a non-starter, I'd let them talk me up to $500 and then leave my contact info and walk away regretfully. Always praise what the machine had once been (if you want it), but regret how much time and effort it will take to get it making good parts again to suit your current needs; and be honest about your high limit. If you make a deal, be sure to try to find the steady rest and any other missing accessories.
smt