Walmart offers The First Years On-The-Go Booster Seat in Multi, model no. Y7392CA1, for $13.40. (Target and Amazon have it for the same price, via in-store pickup and Prime, respectively.) Opt for in-store pickup to avoid the $5.99 shipping fee. That's at least $7 less than you'd spend at another local retail store. Designed to support up to 50 lbs., this self-inflating booster seat features a T-restraint and carrying handle.