Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (137.53 USD): BGToys8
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply 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
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for T-MOTOR U7 V2.0 KV280 KV420 KV490 24V RC Motor.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).