Newegg offers the Battery Tender Jr. 12-volt Battery Maintainer, model no. 021-0123, for $21.99 with free shipping. That's the lowest total price we could find by $3, although we saw it for $2 less in November. It features a 4-step charging program, automatic shutoff, 12-foot output cord, and compatibility with all lead-acid, flooded, or sealed maintenance-free batteries.