should not you be the one with the stall handing out freebies?
it sounds like you are trying to approach businesses with in-place suppliers/distribution channels
who are at the trade show to make new sales,
and you want them to contemplate the exact opposite to become buyers
while they are handing out their free samples to potential customers,
you are going to give them a sample that they are going to have to store somewhere and think about long after the show ends
do you have a business card attached to the tee's?
are you going to be handing out your samples the first day or the last day?
tough call, i'm not even sure you can walk into a trade show and start trading on the floor without having paid for a stall
maybe a better approach would be to take a sample, ask how much are they paying
give them a business card and a short spiel