Here’s a video of a low-cost Robot Arm built by Ganeev Singh at JMoon MakerSpace. This arm was built for submission of a project as part of the Introductions to Robotics MOOC.
The project uses 2 servos (instead of the usual steppers) and achieves a pretty good result. The black servo in the video is an old 3.5kgcm servo we keep here at the makerspace for testing purposes, and the blue servo is an SG90 Mini Servo – Clone.
The original problem statement: