Hippo pool or zebra pool, both with built-in sprinklers, $10.00 at Walmart

Walmart has got this inflatable Hippo pool or Zebra pool for $10.00 with free in-store or FedEx office pickup (or $2.97 shipping).

The Zebra pool is 6' 1.5" x 5' 1" and the Hippo pool is 6' 2" x 5' 1".  They both have built-in sprinklers (connect it to your garden hose) and hold 28 gallons of water.  

(Cheaper than day camp.)