You can get a good silkscreen starter kit at most art or craft store. Speedball makes a nice one that includes a screen, mounting base and hinges (important if you intend to print more than one color on a design) masking and stencil materials and a few bottles of colored ink to get you started.
It is NOT very expensive.
You can also make your own, but it is not much cheaper to buy the materials than the cost of the kit.
Hello, I know an online printing company Design2Express that provides custom T-shirt printing you could ask them about your certain details.