B&H Photo is offering the TP-Link HS110 Kasa Wi-Fi Smart Plug with Energy Monitoring (2-Pack) for $30 with free shipping. No sales tax in most states. Normally $50. clip the 40% off coupon on the item listing to get the discounted price.
This is a 2-pack, and these are the ones with energy usage monitoring.
http://www.bhphotovideo.com/c/product/1276272-REG/tp_link_hs110_kit_hs110_smart_plug_with.html
Manufacturer’s product page: http://www.tp-link.com/us/products/details/cat-5516_HS110-KIT.html