If you can find a 3-D printer nearby, you can use PLA (Poly Lactic Acid) or ABS (Acrylonitrile Butadiene Styrene) at least for the fingers considering the required stress resistances involved for your robot model. It is straightforward to bring a CAD model of your robotic gripper into STL file representation and print these in-the-house. I wouldn't recommend these material to eventually 3-D print/fabricate your robot body, but it all depends on the actual size of your model. If you design it modular, you can 3-D print bits and pieces and then move on to assembly.