Hi Heath, 150 playballs would occupy approximately 3 cubic feet, so they would not cover the floor. You would need a few thousand balls to cover the floor several balls deep, and that many playballs would likely ffall out through the entry opening. It is not recommended to use this inflatable as a ball pit, but the Princess Palace Combo does come equipped with a mini ball-pit at the end of the slide if you're interested in a similar product. You can view that item here: http://www.blastzone.com/princess-palace-inflatable-combo-with-slide Sincerely, Blast Zone Support