This is my robotic arm. I created this for the butler robot I am making. Here is a link to it https://www.instructables.com/id/Open-Source-iRobot-Butler-OSIRB/
The plastic is from a old container top i had and the DC motors came from an old toy.
The hand is made from soda bottle plastic and is constructed like a hand grabber toy from Toys R' Us. The motors are mounted on the shoulder for basic movement and on the hand to grab. the motor on the hand tightens some wire in the fingers and makes them close.
It is all controlled by an Arduino board and an Arduino Motor Shield R3. The motors are attached to the screw terminals on the motor shield.
This whole project cost about 67 dollars.