Good cassette player?

Actually, with the infancy resurgence (there are musicians releasing content on cassette, if you can believe it), a fully functional restored deck can fetch a fair amount of money. And actually the higher end ones sound pretty decent, depending how the recording was made. 
If just doing payback you’ll want to know what tape formulation and what if any noise reduction was applied to have the capability to set bias, EQ, and NR to appropriate/matching settings. 
If you are going to record, you will want a 3-head deck to monitor what is being recorded real time.

Try to find the same model deck you recorded them on (in good operating condition) and use single ended IC's as already mentioned.

Otherwise just send them to a transfer service (T/F to CD and/or a memory stick).

DeKay

I remember much better treble extension in AIWA deck equipped with HX-Pro (bias servo), but it was only for recording.

some nice refurbished Nakamichi sometimes available at decent prices....you might want to make sure the tapes are still good before you spend money...sometimes they decay badly, physically and sonically...

Save your money. Most likely these cassettes are not usable anymore. I hate to be the bearer of bad news, sorry.