Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
Coupon (137.53 USD): BGToys8
(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): BG11924a, TTBLACK5, BGf37638, JanBGCoupon8
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Price history (for all/most countries) for T-MOTOR U7 V2.0 KV280 KV420 KV490 24V RC Motor is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).