Staples offers the refurbished Motorola Arris Surfboard 600 Series DOCSIS 3.0 Broadband Cable Modem for $29.99. Plus, Staples Rewards members bag free shipping. (Not a member? It's free to join.) That's $10 under last month's refurb mention and the lowest price we've seen. (It's the best deal we could find for a refurb today by $15 and $50 under the lowest price we could find for a new one.) It features download speeds of more than 600Mbps and upload speeds of more than 100Mbps. Deal ends May 25.
Note: No warranty information is provided.
Update: Shipping info has been corrected.