Amazon Warehouse Deals offers Prime members the used Arris SurfBoard DOCSIS 3.0 Cable Modem in White, model no. SB6141, for $21.50 $22.87 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $8.89.) That's $3 under our January mention and the lowest total price we've seen for it in any condition. (It's also $10 below the best deal we could find for a refurb.) It features data transfer rates up to 343Mb/s, support for IPv4 and IPv6, and enhanced network management. Note that it may not be compatible with all service providers.

No warranty information is provided.