GM816 Anemometer is for $12.99 (in Banggood). You can create price alert here, copy coupons and view price history. Best price?
Latest coupon and price update (UTC):
0-30 m/s with Temperature Measurement
Banggood ($12.99)
Banggood warehouse is located in China. There is no active coupon in my database right now (for Banggood). Well, is it a good price anyway? Maybe there’re no more promotions for this item, because current price is higher than average (which is equal $9.71)
Link: Banggood product page
Price: $12.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 502C6B, TTxBG10, TISPrime01, Tools1, BGM1TOOLS88, BG20236Tool, BGTOOS729
(probably won’t work, but you can try them out)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Check out price history chart (for all/most countries) for GM816 Anemometer.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).