If you have always had an urge to mold something (small) of your own, and if you are near the Bay Area, Techshop has classes and equipment for reasonable prices:
2nd this - I took the molding class, and it's surprisingly easy to use. The real issue is that moldmaking is hard. The Tormach is a small piece. Still though - crazy that small scale injection molding is that accessible.
3d Printing is better suited for prototyping and Injection molding is where you take it once you need a bunch of parts made because a 3d print can take minutes/hours, while an injection molded part takes seconds.
Injection Molder: http://techshop.ws/class_signup.html?a=1&i=43224759
Tormach CNC Mill: http://techshop.ws/class_signup.html?a=1&i=43094304