Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (25.49 USD): BGC15
(CouponsFromChina.com tip: just apply this code 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): xfd20, BGventilador, TTxBG10, BGxiaomi158, SPT20, AFfbG10, BGC15817, 0e7f33, BGTS204, FBCOUPON1, BGTRIP01, BGSUU45, bGhOnEy10, BgoFErTaSchInA10
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Guildford Handheld Fan.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).