Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Only one coupon available!
Link: Banggood product page
Coupon (9.29 USD): PICODICOM
(CouponsFromChina.com tip: coupon code has to be applied in shop’s 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): 50DGPO, 0404digoo, BGAPPLIANCE, BGHHFANG, BGHG522
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Digoo DF-002 Portable Cooling Fan.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).
still as PROMO from US-warehouse via international shipping available.
($5.43 + shipping)
I can only see CN warehouse
actually there’s a working coupon