Motorola SB6121 SURFboard DOCSIS 3.0 Cable Modem for $64.99 shipped. It is sold by Adorama through Amazon. Here is a screenshot for reference. It has IPv4 and IPv6 support and speed over 100Mbps in both directions. Having your own cable modem often means you do not have to rent one from your internet service provider (ISP) with a monthly rental fee, which saves money in the long run and this is also a better cable modem than most modems from ISPs.