Step one of any successful droid acquisition plan requires a solid foundation in robotics and engineering. You're going to need to get your hands dirty with soldering irons, circuit boards, and wires.
Avoid the dark path of DIY disasters by investing in a good quality 3D printer, like the Step One: Investing in a Good 3D Printer.
Step One: Building a Robotic Arm | Step One: Coding the DroidDon't forget to get your hands dirty!