Deal Time Plus via Amazon offers the used Cisco DPC3010 DOCSIS 3.0 Broadband Cable Modem, model no. AAC4002-10112234, for $29.95 with free shipping. That's $10 under the lowest total price we could find for a refurbished unit (this one is used). It features support for Gigabit Ethernet and USB.

Note: No warranty information is provided. Also, this modem may not be compatible with all service providers.