While the item listing for this device that has 350 reviews is $89.99 on Amazon there is another listing also on Amazon that has only 139 reviews, but is priced at $69.99 .
The difference apparently is the $90 unit is being sold by the “TP-Link Store” (I’m guessing that is TP-Link’s outlet for refurbished units) and is “Eligible for Return, Refund or Replacement within 30 days of receipt” and I don’t find a warranty mentioned. Meanwhile the $70 unit is sold by “the Amazon Renewed Store”. and states “This product is eligible for a replacement or refund within 90 days of receipt if it does not work as expected.”
Sounds like if you are getting a refurb instead of new, that the $70 unit is the best deal, as it gets an AMAZON 90 day warranty, this one only the standard WOOT! 30 day return window, and the TP-Link on also only 30 days.
Wish I’d seen the $70 dollar ones before I bought mine (new, caught a "flash price of $95 on Amazon, but at $70 I might chosen refurb…).