I'm looking into making miniatures for tabletop RPG games. 15mm and up (probably maxing out at 120mm, with most at 30mm). The miniatures will feature objects that should have an organic appearance (i.e. faces and wood) but also objects of a metallic nature (i.e. armor and weapons) and cloth (clothing). I expect most or all would be printed in plastic.

I'm an IT guy with no 3d printing experience, no CAD experience, no experience, really. Doing research, it would appear there are a great many different programs, and each seems suited for different things. What free programs would you recommend I start learning with?