Newegg offers the refurbished Arris SurfBoard DOCSIS 3.0 Cable Modem, model no. SB6141, for $34.99 with free shipping. That's $5 under last month's refurb mention and the lowest total price we've seen. (It's the best for a refurb today by $10.) It features 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.