This is a very strong robot arm with a 1-meter reach you can build for less than $500.  

The arm I built has a single shaft NEMA 23 stepper motor for the base motor to rotate the arm around.  The 2nd stepper motor at the bottom of the 1st arm is a dual shaft (SUMTOR NEMA 23 57HS7630B4D8 3V 4.5A) very strong motor to lift plenty of weight, the 3rd stepper motor is a dual shaft NEMA 17 (RobotDigg NEMA 17 17HS5005-20BM 3V 1.5A) another fairly beefy motor.   The rest are standard size servo motors.  You can use a normal servo motor to hold the tools or a gripper, or for real fun use a continuous rotating servo motor and play with the various tools I've included in the kit.  

I'm using FlowBotics Studio connecting Windows 10 via BluetootBee on a SSC-32u servo motor controller that is wired channels 16, 17 and 18 to Pololu.com TIC 36v4 stepper motor controllers while channels 0, 1 and 2 control the servo motors direct.  The power in is divided as direct to the TICs for motor power while a tap off that goes through a Buck Converter to bring the voltage down to 6V for the SSC-32u to drive the servo channels and logic.  

Wiring is fairly simple with jumpers taking servo channels OUT to TIC RC IN and GND.  The TIC controllers grab power from the main motor power IN (should be about 24V to 30V at 10A).  

Not having a bench power supply I cannot run everything at the same time.  The system really needs about 24V to 30V 10A power supply to handle all the motors.  All I have is a 12V 3A wall-wart so hence no demo video unless I can get a good bench power supply.