I was just at an estate sale a couple of weeks ago with 8 tracks and a working player, 3 typewriters. Each of them went for under $5 bucks.
I was joking--but the ones you found may be worth a fortune on Antique Roadshow in about 50 years. Beter go back.
personally, I never got an eight track to work for more than a few weeks before it started eating the tapes.