Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
Coupon (35.05 USD): BGGAL8
(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): BGSKUA73500, BGH6051, AFfbG10, BGBFAFF2019, BGCITYADS2019, BGH605, BGVDay10%off, 0e7f33, BG10BC, BGAFF10OFF, bGhOnEy10, BGISDTH605, BGBC1, BGdragonBoat, BGSS10%SW, bgshOOp10, BGRC902, BgoFErTaSchInA10, BgcLuBofErtA10, BGCuponation10, BGBCSpring1, BGDAVIS, BGHONEY2110, Parts8, BGRCBC11
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for ISDT H605 Air 50W 5A 2S-6S RC Battery Charger is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).