Whatever robot you buy, get a net to accompany it. Otherwise, you'll spend at least double the amount of time picking up the balls as you'll spend playing.
If you get a table-top robot like the Tibhar Junior or an iPong, this one works perfectly well and is only 30 dollars.
> iPong Carbon Fiber ball ne
Is this the one you have or referring to? https://www.amazon.com/iPong-Carbon-Fiber-Table-Tennis/dp/B00GMERYMA/ref=sr_1_1?ie=UTF8&qid=1487457276&sr=8-1&keywords=iPong+Carbon+Fiber+ball+net
If it is, this is one I had to return because I couldn't get it to mount.