Price history, coupons and price alert are available on this page. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Triple Feed Patch-1 5.8G 9.4dBi FPV RX Antenna For LHCP RHCP SMA RC Drone
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($17.98): BGGAL8
2. ($17.98): BGJON8
3. ($17.98): BGRCParts8
this code has to be applied in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): Parts8
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for GEPRC Triple Feed Patch-1 5.8G 9.4dBi FPV Antenna.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).