Walmart offers the Evenflo Big Kid Sport High-Back Booster Seat in Goody Two Tones or Peony Playground for $19. Opt for in-store pickup to dodge the $5.99 shipping charge. That's $11 under our May mention, the lowest price we could find by $13, and the best price we've seen. It converts to a backless booster seat and features 6-position height adjustment, energy-absorbing foam lining, a machine-washable removable seat pad, and two cup holders.