Amazon seems to be running a bunch of sequential flash deals on echo devices, so I don’t know how long this one will last:
( these are the newest generations of each of these two devices. The first generation echo was so successful that they took a while before they came out with the second. The dot needed a little more tuning to get the sound right. 
)
If you buy them separately from Kohls during black Friday, they are $69 + $24 = $93
and you get $15 Kohls cash. Add $7 more to your purchase and you have $30 Kohls cash that you can use towards other purchases. On top, if you are rewards member, you get $5 coupon for your 100 points. Total out of pocket $65.
Good catch, but just be aware that Kohl’s is a " quantities limited, no rainchecks" doorbuster on both, so no guarantee you’ll get that price.
Since I only have dots what is the use case of the big echo? My dots are hooked up to AVR so sound isn’t an issue.
Then you don’t need The regular echo. The only advantage is the sound quality. 
I think the microphones on the echo are a bit better than the dot, as well, but it is up to you if it is worth the expense.
I know people…that know people…that know people…that know people… 
I have my living room Dot connected to my AVR, but I do not like to keep my AVR on all the time. So I created a Harmony activity called “Receiver” which turns on my receiver and switches to bluetooth. I just tell Alexa to turn on receiver when I want to stream.
The same deal is available online @ Kohls. After all discounts and coupons my total out of pocket for echo 2nd gen + dot 3rd gen would be around $60 ( $30 Kohls cash, $5 Yes2You + $5 no hurry ).
Kohl’s was out of stock when I just checked. I think they had limited quantities on most of the Amazon devices.