Walmart offers the Kid Motorz Hummer H2 6-volt Battery-Powered Ride-On in Red for $149.82 with free shipping. (Amazon charges the same; Target charges the same in Pink.) That's the lowest total price we could find by $37. Features include a 45 minute run time, 2.5mph top speed, and working horn.

Update: The Walmart item has increased in price; however, the offer from Amazon and Target are ongoing for $149.86.