If by that you mean selling band merch, then yes. Using an online store is cost inefficient if you want to produce on a larger scale. Buy your own screen printer (cheap ones around $100 better go up in price) and do it yourself. Save a lot of money over using any other service.

when cafe press first came out I made some money by putting popular memes on coffee mugs and tshirts. (we didn't call them memes back then. it was a long time ago)

it worked for me because there was no investment except time. it's different now because tons of people are doing that. plus if it's the same as it used to be you get like $1 for selling a $15 shirt.

If you do at least 100 shirts you should be able to get some shirts with 1 color printed on them for $3 each. If you do them yourself they will be cheaper because a lot of that money is in the labor. Of course if you can sell those 100 at $10 each you make $700 bucks.

The question is can you sell them?