Newbie buying used for casual use.

that is way too much for that bike. I'd offer $20.

If you are on a budget look at a pawn shop, craigslist, community bike shop.

even better trade some time at a community bike shop for a ride.

check your local bike shops for used bikes. these may be more expensive but typically you will get something much better.

It may be a great investment because nobody is gonna steal that thing.

But I'm sure better bikes can be found for 80 dollar.
It's sometimes amazing how cheap older bikes can be that once costed a couple of thousand.
However I'm handy enough to put a new chain, sprocket, cassette and cables on. About every part that moves actually. It will set you back another 100 dollar but it will ride virtualy as new. The bike has to be worth it and I doubt if this one is.
If you can't do that yourself then choice is limited and you will have to trust the seller or take it to a bike shop before you buy. Main costs are the drive train. New tires are the easiest to replace.