With stock varying by ZIP, Walmart offers the Philips Avent Fast Bottle Warmer, model no. SCF355/00, for $29.24. (Amazon charges the same with free shipping for Prime members.) Opt for in-store pickup to avoid the $5.97 shipping fee. That's the lowest price we could find by $6. This BPA-free bottle warmer heats 4 oz. of milk in three minutes.