Not sure where you're located, but do you have Spencer's or Hot Topic where you live? I have been to Spencer's recently and found that they had some new Ant-Man shirts coming in. I don't remember if it was this same one that you're looking for, but it's worth a shot. I'll keep my eyes peeled. If I come across one in my area I'll buy it and get your info and we can work out the details later
Acheno84 makes a really good point. I would check out a local hot topic, if you have one. They tend to carry a ton of Funk Pop items in stock. I'd also look into Ebay. Ebay might be your best bet if it is a limited edition t-shirt. If it's not limited edition, I would still look into Ebay for a brand new shirt, since people buy these shirts in bulk for resale. You might be paying a hefty price for the shirt if it's not easy to find, but if you really want it, that's your best option.
Another tip: Check your local CD/DVD store. I know that ours sells tons of t-shirts, and they may actually have this one. I have countless connections in the mall, and I've sent out a memo searching for your shirt. Fingers crossed that my minions can find it for you!
I actually got a pretty good laugh at this one, because I am not sure which I would prefer to have, an Ant-man figure or a Paul Rudd figure. I think I might have to go with the Paul Rudd. He is just a little guy and one of my favorite comedy actors, so he would be well represented I feel like. Maybe one day they will start coming out with celebrity ones.
If you cant really find a shop that has an available design of that shirt or if it is too expensive. Why not to buy a shirt and tell the staff of the t - shirt printing shop to use that design and print it to your shirt. Now a days it is hard to find that t shirt design I think. So the only solution in that is to print on your own. But make sure that it is not copy right. Find a free design if you will copy.
I think it's kinda funny that it's so hard to find a small antman shirt, may be it's too small and shrink-ed to the size of the ant. I am sorry if you find this corny. haha. Still i am hoping that you find one soon, i am confident it's just out there somewhere.