Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. I couldn’t find any coupon for this product on latest product update.
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): 502C6B, d8f2bb, bGhOnEy10, BGJXD509W, BG509W, 7d18f7, 13f142, BGDAVIS, BGMATT7
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for JXD 509W Quadcopter is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).