You don’t have to spend a fortune to get your hands on a trainable robot arm. Take LittleArm for instance. It is a 3D printed Arduino robot arm for STEM students. This 4-axis robot has an interchangeable gripper. This is an open source product, so you can add sensors and customize how it behaves.
This robot arm is controlled by Arduino. The kit ships with an Arduino Uno, mini breadboard, 3D printed plastic components, servos, and everything you need to get started.