By David Goldman, Heather Kelly and Jose Pagliery @CNNMoney December 18, 2014: 4:10 PM ET
TCP connected light bulbs, $80
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Did you leave the lights on? Your smartphone can tell you -- and it can turn them off. Or dim them. Or you can set a timer. TCP's connected LED light bulbs cost about $20 each, which isn't much more than standard LEDs. And they'll last you for more than 20 years.