Dan - are you interested in a collection of blanks?
I have about 1500 in various lengths, a holdover from the days when cassettes were the only option for small bands and ensembles, since CDRs were too expensive.
I know you're probably looking for music. Cassettes can sound really very good, esp. with a decent player. Wow and particularly flutter were the achilles heel of the medium - that's why you need a decent player to enjoy them once spoiled by the perfect pitch stability of the CD format.
I have a bunch of good players for sale - maybe I should advertize them in Marketplace.
When I first got into mastering, about 1992, our first CD burner was $30,000 and blanks were $25 ea. That burner was a flop, so we had to buy another since the first was out of warranty. That only cost us $15,000. You can bet CDRs were not used casually!