Tyler Lizenby/CNET

Digital assistants grow up so fast.

Three years ago, Amazon unveiled Alexa, its software that lets you turn the lights off, play a song, or check flight info with your voice.

The ecommerce giant is celebrating the anniversary with a big one-day sale on Echo devices and other gadgets that have Alexa built in.

For example, you can save $33 by buying a three-pack of Echo Dots. Or you can save $50 buy nabbing three second-generation Echos. The Amazon Tap, the company's portable bluetooth speaker that usually costs $130, is just $80. Among the deals for third-party devices is the Ecobee smart thermostat, which is going for $209, instead of $249.

In the three years since Amazon unveiled Alexa, the digital assistant has been the unexpected hit in the nascent smart home market. Echo devices own 73 percent of the market. Google, with its Assistant software and Google Home devices, is far behind with 27 percent, according to a report published Monday by Consumer Intelligence Research Partners.