Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (14.44 USD): BGSMOFF
(CouponsFromChina.com tip: you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): 19EX02, 0404digoo, 16EX02, BG14EX02, 2019SPEDM, BG11EX02, bgssaff9, BG9EX02, BG10EX02, BGDG002, aff7off, BGDG002ES, BG30BTS, BGEX002, BGSAMH, 20%DG422, BGSM15
(these coupons are old, so probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for DIGOO DG-EX002 Weather Station? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).
Hi, the 9.99 coupon no longer works it says “coupon has a limit of 500 uses” or something very similar to then 500 limit
Create price alert, maybe it will be active again