$18.99 – Center frequency: 5.8 GHz, Radiation efficiency: 75%, Axial ratio: 1.05(0.38dB), Antenna gain: 14.4 dBi, Matching: S11 < -30 dB / VSWR < 1.065, Half power beam width: 30° (horizontal and vertical), Bandwidth: 660 MHz (5.47 – 6.13 GHz).
When I was updating this page the price was $18.99 for 150mm Triple Feed Patch 5.8GHz 14dBi FPV Antenna (in Banggood). Just check coupons out (with price alert and history). You probably want to know what is the best price?
Latest coupon and price update (UTC):
Banggood ($18.99)
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood. Isn’t it too expensive? It looks like it’s a good price (lower than average ($20.61)).
Link: Banggood product page
Price: $18.99
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): Parts8, BGJON8, BGRCParts8, Tabby20, BG1efeb0, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, BGRCT10, BGf610c0, BGJUNEGSG9, BG8ReviTrage, Cuponation9, BGToys8
(I don’t think these’re gonna work, but you can try ’em out anyway)
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.
Price history and price alert
Price history (for all/most countries) for 150mm Triple Feed Patch 5.8GHz 14dBi FPV Antenna is here. The lowest price was: $12.99.
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)).