The Echo Show 21 is a great smart home hub that’s $80 off

Echo Show's 21 attached to the adjustable stand, which is sold separately (and also discounted). | Image: Amazon Split between buying a smart calendar, a kitchen TV, a smart home hub, and a smart display? Amazon’s Echo Show 21 is all of those things in one, with a huge 21-inch screen. You can use it to control your smart lights, glance at recipes, watch TV shows, and more. Currently, Best Buy and Home Depot have the product on sale for $319.99 (usually $399.99), matching the lowest price…