Great job with this project. I would try striking some kind of affiliate deal with sites likeImgur or get advertising on a meme subreddit. $25 might be a little high for an impulse tsirt buy, but it could get some hits.
One-off t-shirts are expensive. I recently got 8 t-shirts made by Custom Ink, and each one was $40. I didn't even choose the expensive American Apparel shirts, either.
Custom Ink is probably one of the more expensive companies (and I chose them because of their excellent customer service), but you get my point.
