Amazon offers the Hot Wheels Color Shifters Sharkport Showdown Playset & Swamp Raiders Playset Pack for $18.96 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it adds $6.81.) That's the lowest total price we could find by $15. This playset bundle includes a color shifter car and several color-changing zones.
Orders placed via Prime by December 22 are guaranteed to arrive in time for Christmas. (The deadline for standard shipping is today, December 19.)