We got the 500 pack for a kid birthday party and it was a hit! 500 sounds like a lot, but they are smaller balls so it perfectly filled a larger kiddie pool.
2-6 year olds were launching themselves into the pool and they didn't crush the balls. If you hold one and crush it, it will bounce back. Very satisfied. Would have liked to pay a bit less for the product, but I had my heart set on it and I don't regret it.
Keep the box that it comes in to store or use a trash bag….storage may be inconvenient unless you have a garage.