Dimensions: 26(W)x26(D)mm, Output power: 25mW: 100mA/200mW: 200mA/400mW: 250mA/600mW: 320mA@12v, 20x20mm(hole), Weight: 5.4g(excluding antenna), Power supply: 5v camera@under 0.3A max, Port connector: Solder Pads, MIC, Input voltage: 7-24V, Antenna connector: MMCX/UFL, Extra feature: Smart Audio/MMCX+UFL connector, Range: Up to 2km with omnidirectional RHCP antenna.
Basically copy coupon, view price history or create e-mail price alert. Best price?
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. Hmmm… There is no active coupon in Banggood at this moment.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): BGFX3, Parts8, BGBCFPV, BGFX3Q, BGBCBG10, 502C6B, BGOTC21, 0e7f33, FBCOUPON1, BGPLHD, BGCuponation10, BGDAVIS, BGRCParts8
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for AKK FX3-ultimat FPV Transmitter? There we go. The lowest price was: $14.99.
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)).