Amazon is running a new promotion that automatically takes $10 off the purchase of 4 Echo Buttons. Echo Buttons are sold in sets of 2 for $19.99, so when you add 2 of the sets to your cart, you’ll see your total automatically reduced to $29.98 at checkout. This is the first time that Echo buttons have ever been on sale. Echo buttons give you a physical way to interact with skills on your Echo devices. They’re still a very new concept, so developer support is limited. Right now, there are 25 Alexa skills that use Echo Buttons. Most of the best ones are games, such as Simon Tap, which requires 4 buttons, and Trivial Pursuit Tap. This promotion ends on April 23rd.