Walmart offers the LEGO Creator Modular Poolside Holiday Kit for $21.99. Opt for in-store pickup to avoid the $5.99 shipping charge. (Amazon charges the same with free shipping for Prime members.) That's the lowest price we could find by $2. It rebuilds into a skate park or music garage.

Update: The price has increased at Walmart; however, Amazon still offers it for $21.99 with free shipping for Prime members.