Port for easy connection to 4-in-1 esc (SH1.0 8P), Supports 3-6S Lipo, Built-in 5V 1A BEC output (Buck), Solder pads added for VTX and Camera Control (next to Video pads), F7 MCU processors, Built-in 8V 1A BEC with LC filter output for the camera and VTX (Buck), STM32 controls OSD chip over SPI in DMA mode (Betaflight OSD), FrSky R9 MM receiver in protection box, Two gyros onboard: MPU6000 for sampling up to 8khz and ICM20608 for sampling up to 32khz, Built-in sensor damper, More caps to reduce power noise, 30.5×30.5 mm mounting holes.
Just check coupons out (with price alert and history). What is 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 coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There are no coupons available at this moment in Banggood.
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!
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BGR9F7, TTxBG10, aff7off, BGRA20, BGFrsky, BGfrsky10, BGaDmITAd, BGRCCD30, BGFRSKY15, BG10FrSky, BGBFAFF2019, BGAFF7OFF, BGTT10, bGhOnEy10
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Do you need price history chart (for all/most countries) for FrSky New 900Mhz R9 MM-FC RC Receiver? There we go. The lowest price was: $45.99.
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)).