Aliexpress
Click here… to search for Lumenier Micro AXII MMCX 5.8GHz 1.6dBi FPV 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 (17.99 USD): BGTT10
Coupon (18.59 USD): BGAFF7OFF
Coupon (18.99 USD): 13f142
(CouponsFromChina.com tip: apply it in your 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): BGBCBG10, aff7off, bgchinafest, BGOTC21, BGBFAFF2019, BGCITYADS2019, bGhOnEy10, BGSS10%SW, bgshOOp10, BGHALLOWEEN
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for Lumenier Micro AXII MMCX 5.8GHz 1.6dBi FPV Antenna.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).