1998 Blazer problems

Where do I start? Transmission revs up, can't go over 20mph. When driving high speeds, plumes of black smoke occasionally pour out the back, then stop. (don't know what that's about, doesn't seem to be losing oil). Bearing out in one wheel. Getting rid of it, How much should I ask for it?

Welcome to AF.
Without looking at it and knowing what the problems are.
We can not really say.
Not to hurt your feelings.
If your are scraping it or selling to a bone yard Scrap metal is up so a bone yard may go a 100$ for it.
Good luck
MT