Returnboard or robot for under $100/ $100 for intermediate players?

What is something you would recommend that is under $100 I can hit off of/ with? Would you recommend a robot or a returnboard for intermediate table tennis players If a robot: Which one for cheapest price for intermediate players? If a returnbard: Which one for cheapest price for intermediate players? Can you practice underspin, topspin, and sidespin with returnboard? How is a returnboard better than putting the table next to the wall and hitting the ball at the wall? Thanks again,your best friend Bman489