I've been looking for an inexpensive device to get my car to play songs from my phone. I've got a wired cassette adapter, but the wires inevitably break (I have a teen that uses it too). I found this bluetooth cassette adapter, but it's $60 and only lasts 8 hours per charge.
Is there an adapter that lasts for at least 15 hours of playback for less than $40, perhaps one that uses the cassette spindle drive to augment (or replace) the battery altogether?