I bought the offer that came with a basketball and a volleyball for the beach. 58€ including shipping.
The positives:
Good quality plastic.
They include a ball inside. (basketball, water polo, volleyball)
They inflate in 3 minutes with your mouth, no need for a pump.
They are great for the pool.
The negatives:
They don't work at all in waves. So the sea must be relatively calm.
The kids and their cousins played with them a lot. Ages 8-13. Even outside the beach.
I added weights (I made them with string and water bottles, I put one on each side)
and they became much better in the sea.