Are you referring to tee shirts or art? No one there is selling tee shirts per say. All the major tee shirt companies are there, and a lot of transfer art companies. If you’re looking to sell your art you can try and talk w/ the transfer companies at the show, but obviously their first priority is to sell their stuff.
I would advise collecting information on the companies you want to approach and get a contact name at the show. If you happen to get into it w/ the right person, great. But I would plan on approaching these companies after the show.