In my hometown there used to be at least 2 shops (yes, shops) that sold bootlegged/pirate software. Mostly games but they had all sorts of business software as well. This was earlier than the 90s.

The shops themselves were not in the software business. One of them was specialised in turntable needles, and it was pretty popular. You had to go to the counter and specifically ask for "the menu" in order to access the "other side" of the business. It was an open secret though, as there was a lot of traffic in the shop for "the menu". You'd choose what you wanted, paid for your copy and leave with a bunch of floppy disks with it. They charged extra for the actual disks but you could also bring your own and only pay for the service.

If you mean electronic music bootlegs, then I don't see why the media or the format is that relevant. It's still just regular bootleg, and it's been popular since whenever copying and selling music was made possible.