ON THE INTERNET
My first warning is—and I can’t stress this enough—do your research! Many people all over the world make reproduction T-shirts and price them insanely high in an effort to, well, rip you off. Tip No. 1: Look for tags (Anvil, Gildan, etc.) from manufacturers that were popular decades ago and then do some Googling to figure out whether it’s a shirt from an actual concert or official band merchandise. Tip No. 2: Don't be afraid to message the seller and ask questions. A lot of my most precious finds on the Internet have come from the most random sources (e.g. some dude in Kentucky cleaning out his basement), but there are also many reputable and established sellers (like one of my faves, VTGDallas on Etsy) who solely collect and sell vintage band memorabilia and can be trusted.