 Illuminate Data says music lovers purchased more than 436,000 cassette units in the U.S. last year. That's more than five times more than in 2015, but way less than the $450 million back in 1988. One reason for the recent growth, at about $10 a pop, cassettes are way cheaper than the $35 a vinyl album might set you back. Denise Pellegrini, Bloomberg Radio.