I checked twice. Yes, it’s really $10.99 (in Banggood). Polarization: Right Hand Circular Polarized /RHCP, Frequency: 5.8G, Gain: 5dBi, Connector: RP-SMA /SMA, VSWR: <1.3, Impedance: 50Ω, Radiation: Omni.
Updated:
Banggood
Warehouse in China.
Link: Eachine K-Loverleaves 5.8G 5dBi 6 Leaf Clover RC Antenna
Price: $10.99
Additional Banggood coupons:
1. First page
2. Second page
Aliexpress
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Price history and price alert
Do you need price history chart (for all/most countries) for Eachine K-Loverleaves 5.8G 5dBi 6 Leaf Clover RC Antenna? There we go. The lowest price was: $10.79.
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)).