There are a number of Teespring alternatives, including sites that allow for community voting, here: http://nstr.co/1S0v3X5

Also, one of the last links has a case study on how one company sold $1200 on Facebook alone using Teespring.

There are platforms that allow you to dropship your shirts less expensively, but you will need to compare the trade-off in customer service and features that Teespring boosts.

All the best,
-Shaun