I'm old I can remember we had these little cases that held.. I dunno, maybe 60 cassette tapes if they were double sided? And a typical weekend activity for bored suburban young teenagers was to spend the paper route money on a big chunk of blank tapes, which weren't even all that cheap, trade cases with a friend, and spend hours copying them.
How else would I hear new (to me) music? Radio sucked and there wasn't any internet. I guess for a short bit we did have an MTV that was a bit all over the place, before it locked into the 'same 6 videos every hour' format and then the 'no music whatsoever' format.