Maybe you don't have any friends that are in a band, but if it's the band members or friends of the band selling the merch, they are getting 100% of the profit. They design the shirts, they pay for the printing of the shirts, they then sell the shirts directly with their own hands. There's no middleman taking cuts. Now, if you're buying their merch from some 3rd party website, that site probably takes a cut. Some bands selling merch on their own website could still be coming directly from the band if one of them, or again a friend, sets up the site with their own accounts using square/stripe/etc and deals with the fulfillment themselves they are minimizing cuts as well.