OOAK Table Tennis Forum

Hello everyone. I am new to this forum and I have a question. Our coach asked me to look for some info about different table tennis robots. He wants to purchase one or two (have no idea, actually) for our trainings. I know absolutely nothing about what's the difference between any of them, and the coach did not even mention the budget. Here is the list I found: https://recroompick.com/best-ping-pong-robots/. Please, look through these and tell me if you worked with any of those because the price goes from $95 to $650. I'll will come back with the numbers we can afford, hope by that moment will get a couple of replies.