Amazon offers its Prime member the On Networks N300 802.11n Wireless 4-Port Router, model no. N300R-199NAS, for $19.99. Clip the "$10 off" coupon below the price and in-cart, the price falls to $9.99. With free shipping, that's the lowest total price we could find by $10. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $9.03.) It features four LAN ports, dual firewalls, transfer rates of up to 300Mb/s, 2.4GHz, WEP and WPA/WPA2-PSK support, and more.

Note that it's scheduled to ship in one to two months.