Connector: IPEX 4, RF Cable: RG1.13, Cable Length: 85 mm, S.W.R.: <= 1.7, Compatibility: FrSky R9 Mini/ R9 MM Receiver, Frequency: 868/915 MHz, Antenna Gain: 2.0DBi, Width: 168 mm, Weight: 1.3 g, Working Temp: -40~80℃, Impedance: 50 Ω, Polarization: Horizontal polarization, Humidity: 95%~100% RH. Get coupons, create price alert or check price history out! Let’s see what best price is ATM.
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 coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
1. ($11.67): BGRCParts8
coupon code has to be applied in shop’s 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): Parts8, 2020CNY, BGVDay10%off, bGhOnEy10, BGTT10, BGSS10%SW, BGRCRR9, BGRC902, BG11SHOP, BGDAVIS, 13f142, BGradio9, BG70e5fc
(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 T-Type 900MHz RC Receiver Antenna FrSky R9 Mini MM. The lowest price was: $3.39.
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)).