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 (10.79 USD): AFfbG10
Coupon (10.79 USD): affbg10
(CouponsFromChina.com tip: apply it 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): SF2306, 502C6B, SUNFUN, randy988, TTxBG10, 2019SPEDM, bgssaff9
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for DYS SUN-FUN SF2306 RC Motor.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).