Meritline offers the ASUS GigaX 8-Port Ethernet Switch, model no. GigaX1008, for $17.99. Coupon code "MLCM628HP" cuts it to $12.99. With free shipping, that's the lowest total price we could find by $7, excluding the deal below. Note that despite its name, it does not support Gigabit Ethernet speeds.

Don't mind rebates? newegg has it for $17.99 before this $10 mail-in rebate (paid via an American Express prepaid card), $7.99 after. Free shipping applies. Rebate ends June 30.