Flysky FS-A8S FS A8S V2 2.4G 8CH Mini RC Receiver with PPM i-BUS SBUS (Banggood, Aliexpress: 2.4GHz system: AFHDS 2A, No ground interference (Transmitting and receiving 1 m from the ground): >300m, Channel delay: <15mS, Antenna length: 26mm (Not including brass contacts), Item Name: FS-A8S Receiver, Data output: 1.5mm*3 Pin PPM/i-BUS/S.BUS, Transfer method: FHSS, Band width: 500KHz, Display method: LED, Frequency range: 2.408-2.475GHz, Band number: 135, RX Sensitivity: -92 dBm, Input power supply: 4.0-8.4V, Modulation type: GFSK, Brand Name: Flysky, Each channel data: depend on the transmitter, Working current: 40mA, Channels: PPM 8CH / i-BUS 18CH, DSC port: PPM/i-BUS/S.BUS, Size: 20*14*5.3mm, Model type: Multi-rotor, Weight: 1.2g (the best price with coupon)).
Just check coupons out (with price alert and history). What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
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. Only one coupon available!
Link: Banggood product page
1. ($16.21): BG589b2e
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGbe6c63, BGRADIORU, BGToys8, BGMatt2022
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Flysky FS-A8S FS A8S V2 2.4G 8CH Mini RC Receiver with PPM i-BUS SBUS. The lowest price was: $11.99.
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)).