Walmart offers the Cosco Juvenile Top Side Booster Car Seat in Lemon, Magenta, or Purple for $12.38. (Amazon charges the same for Prime members only with free shipping.) Opt for in-store pickup to dodge the $4.97 shipping charge. That's the lowest total price we could find by $12. It's designed for children from 40- to 100-lbs. who measure 43" to 57".