I wish to build a chess playing robot with robot arm as shown on youtube, can anyone please tell me which robot arm would suit my purpose and whether it can be bought second hand or alternatively anybody willing to sell used chess arm robot? Please help out.
You can buy one here: RobotShop
But an arm can be fun to make! If you want to build one, there are a lot of sources to read up on.
Here's a general overview
The 3 general things you need are...
1) to learn forward kinematics -- this will give you a basis to learn the next step
2) to learn inverse kinematics -- this will give you an understanding of the math used in moving your robotic arm
3) to decide on a hardward platform -- stick with the big names, something like Arduino or Raspberry Pi. You'll find tons of code & community resources online.