I have just checked coupons. The lowest price I could get is 52.99 USD for RTF with 2 (in Banggood). Basically copy coupon, view price history or create e-mail price alert. Best price?
Latest coupon code price check (UTC time):
Banggood (52.99 USD)
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood. You probably want to know if this is a good price. Maybe there’re no more promotions for this item, because current price is higher than average (which is equal 51.99 USD)
Link: Banggood product page
Price: 52.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGCAPITALOS8
(I don’t think these’re gonna work, but you can try ’em out anyway)
Aliexpress
Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for 4DRC V28S Drone RTF with 2 Batteries is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).