From 98? You looking at like a Pentium 2. VERY lowed P3 at Max. You won't get anything for it. Its not even worth it. Probably will barely run XP and with how technology is these days any OS older than XP won't be supported on almost anything new theses days. Just drop it off at your local ewaste center lol
I agree with the above. You have more of a pay someone to take it scenario than something to make money from. 😉
There is nothing that can be done on a box that old that can't be done better with modern hardware and software including playing old games. You can always use an emulator to run old titles on modern hardware.
Might be fun for a kid to play with. Might also make the kid mad he's getting such obsolete hardware too!