You can definitely grow relatively big by training with your own weight - just look at the calisthenics and street workout athletes - many of these guys are jacked, and they work with their own weight. It is a matter of training properly, and of your expectations. If you want to be as big as professional bodybuilders, you definitely need to train with free weights and other heavy stuff. If you don't have such an expectation, you can still be in a very good shape by training with your own weight.