Walmart offers the factory-refurbished Motorola Surfboard DOCSIS 3.0 Cable Modem, model no. SB6121, for $19.99. Opt for in-store pickup to dodge the $5.97 shipping charge. That's tied with last week's mention, $5 less than the best deal we could find for a refurb elsewhere now, and the lowest price we've seen. It features support for IPv4 and IPv6 and enhanced network management. A 90-day Motorola warranty applies.