Several years ago a neighbor had a yard sale to get rid of stuff before he moved. He had a couple bikes in the back yard. He said when his kids moved out he was tired of taking care of their stuff, so he left the bikes where they had left them. Not sure how many years had passed but a two inch (~~5cm) diameter tree had grown up through the frame of one of them, so it has been at least a decade that they sat outside.
I went home and did an internet search on one of them. This one.
https://www.sheldonbrown.com/bridgestone/1994/pages/36.htmWent back, handed him the $5 that he asked for it. He got out an electric saw and cut down the tree so the bike could be removed from the tree trunk. And I wheeled it home. (First photo.)
All the rubber and plastic had to be discarded and replaced, even rim strips. Needed new chain, some new cables, new bottom bracket, new pedals, front shifter (used a friction thumb shifter for a while). Re-grease everything I could. It took two days of off and on work to get the bottom bracket out. Added Frame Saver to the frame to prevent further frame rusting.
And it turned into a great errand bike. (Second photo.) For the past decade I had made most of my grocery store trips in summer on that bike.
For the next decade I continued to store it outside, it gets no use in winter. (Third photo.)
I think I put about $50 USD into it. I got rid of a lot of the stuff that filled up my garage, so now I store that bike indoors.
That said, I could easily have found a frame with rust perforations, so it is a roll of the dice when you buy something that has been neglected. I got lucky.