P.O.S.
(The reason so many of these threads keep popping up is that there are so many of these "bicycles" around.)
What to look for? As somebody on another thread wrote (and I'm paraphrasing here), "avoid anything with the 'big disc between the freewheel and spokes', one-piece 'Ashtabula' cranks, shifters mounted on the handlebar stem, or 'safety levers' on the brake levers."
All of these are markers of heavy, old (sometimes not THAT old) clunkers that are better off in the trash. Sorry if I sound like a cranky old guy.