Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
Coupon (302.85 USD): Parts8
(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): 2019SPEDM, BGFlySky, BGFlysky, BGPL18, BGFSPL18, BGaDmITAd, BGFSPL272, BG15PL18, BGFSPL10, BGX7S15, BGCITYADS2019, BGBFPL18, BGFSPL12, BG9NY, BGPL18XN, BGnewpl, BGPL20, 2020CNY, BGVDay10%off, BGFS12, BGPL185, BGpapl18, BGFKY11, bGhOnEy10, BGPL1815, BGflysky11, BGSS10%SW, bgshOOp10, BGRC902, 7bcdf9, BGRCRR9, BGCuponation10, BGDAVIS, BGradio9, BG70e5fc
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Flysky FS-PL18 Paladin RC Transmitter.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).