Newegg offers the TP-Link WiFi Smart Plug, model no. HS100, for $29.99. Coupon code "EMCETGG57" cuts it to $19.99. With free shipping, that's tied with our February mention and the lowest total price we could find by $9. It can be controlled via a smartphone and features scheduled on/off and away modes, 802.11n wireless, and voice control via the Amazon Echo (sold separately). Coupon ends April 25.