I was initially just buying the smart plug at ½ price but for a ridiculously small amount more I could get both as a package. Once I'd set it up for my Mum I went to buy the same for myself but it had practically quadrupled in price. I was very fortunate to buy it when I did.
It has been a godsend to my Mum, who has become increasingly infirm this past year. I have since bought some more smart plugs - a different make, as Amazon's smart plug on its own at its normal price is a bit pricey (and bulky) - and now my Mum can just ask the echo flex to turn on her bed electric blanket, her lamps and even her snuggle electric blanket (so she doesn't have to keep unplugging it). I have also set up the echo flex to ring and text me if my Mum has a fall or needs help (via emergency contact). My Mum can just shout for help and the echo flex rings me. Once I answer, I can speak to my Mum through the echo flex. I didn't know this was possible when I bought it but I thought it should be possible. It was easy to do.
The other benefit of the flex, is that even though it plugs into an outlet, it has a USB port underneath the base so you can charge your phone/tablet etc with it at the same time. The only downside is the Kindle Fire tablet my Mum has, charges very slowly using it, yet her mobile is fine. There is also an accessory motion sensor nightlight you can plug into the USB but it is currently unavailable to buy. Good idea though.
Another problem with the Kindle Fire (an older model - 7th gen), I couldn't update the Alexa app on it (which was needed) so I had to set up the plug and the flex using my Mum's mobile. The actual instructions that come with the kit aren't as good as the instructions on the Amazon website. Once I referred to the website, they were both easy to set up. However, my Mum doesn't have to worry about the app, she just speaks directly to the echo flex just like it was any echo type of kit.
The smart plug is fine. A bit big. I prefer the smaller smart plugs but initially I only wanted one to see if my Mum liked the idea. The plug needs a 2.4GHz Wi-Fi band to set it up. I have found this to be the case with all the smart plugs I have used.