Sell something for me

I produce a line of T-shirts that I'd like to sell in large quantities. I currently sell them one at a time on my website, eBay, and Etsy. The designs would work very well for fundraising. Each design features a silhouette of a different dog breed (and one cat) with the word "RESCUE" underneath. I'll also be adding another line that will feature the silhouette of each of the 50 U.S. states with the word "HOME" underneath, which lends itself to raising funds for non-profits like homeless shelters, Habitat for Humanity, etc. Given that each shirt is printed by hand, the margins are slim, so I need someone who can move large quantities (at the very least, 250 units at a time, but preferably 500-1000+ units).