Aliexpress
Click here… to search for Racerstar MELO F4 Bluetooth Flight Controller on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. Hmmm… There is no active coupon in Banggood at this moment.
Link: Banggood product page
Price: -3 USD
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): AFfbG10, 502C6B, 0e7f33, BGAFF10OFF, bGhOnEy10, BGdragonBoat, BGSS10%SW, BGCuponation10, BGDAVIS, BGHONEY2110, Parts8, BGGAL8, BGJON8, BGRCParts8
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for Racerstar MELO F4 Bluetooth Flight Controller.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).