OrangeOnions offers the My First Wheels Inflatable Ball Pit with 20 Balls for $39.99. Coupon code "BALLPIT" cuts it to $24.99. With free shipping, that's the lowest total price we could find by $24. It measures about 38x29x29".
Of note, any items you add to this order will also ship for free.
From shoes to cookware, if you're willing to pay a little more for these awesome products, you may never have to shop for another again.