Cable Length: 82mm, RP-SMA(inner hole), Skew Weight: 11.5g, Connector: SMA male (inner needle), Case size: 33.5m(w) 16mm(h), Item Name: SpiroNet 5.8GHz Antenna.
Basically copy coupon, view price history or create e-mail price alert. Do you want to know what the best price is?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($22.38): BGBCFPV
2. ($23.40): Parts8
you should apply the coupon 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/i1u
Old coupons (from the oldest to the newest): 5ddbfe, 502C6B, f62884, bgssaff9
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for Fatshark ImmersionRC SpiroNet RHCP RC Antenna. The lowest price was: $11.9.
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)).