Aliexpress
Click here… to search for Flywoo ATOMIC 5.8GHz 3dBi RC Tube RHCP MMCX Antenna on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (10.94 USD): BGGAL8
Coupon (10.94 USD): BGRCParts8
Coupon (10.94 USD): MVC8SPRING
Coupon (10.94 USD): 8BGwbg2204
(CouponsFromChina.com tip: apply code in your basket (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): BG103b13, Parts8, Tabby20, BG1efeb0
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Flywoo ATOMIC 5.8GHz 3dBi RC Tube RHCP MMCX Antenna is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).