Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (23.55 USD): BGherra
Coupon (23.55 USD): BGWELDTOOL
(CouponsFromChina.com tip: this code has to be applied 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): BGHeatgun2, AFfbG10, bg2g00d, TS15prime, BGTEP2, TISPrime01, Tools1, BG11VIPD, Tools3, BGminleaf, BGPowerTool15, BG2020NS, BGWM2, BGPTOOL, BGoh22, BGPToo15, BGRUS15, BG0078cf
(there’s a little possibility that old coupon will work)
Price history and price alert
Check out price history chart (for all/most countries) for Minleaf ML-HG1 2000W Electric Heater.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).