Use coupon and get FrSky Tandem X20S RC Transmitter for $494.99 (from Banggood). Go down and check coupons out. Remember to check price history if it is available. Best price?
Latest price update (UTC time):
, Version: Non-LBT/LBT Version, Item Name: X20S Transmitter with R8 Pro R9 MX Receiver & Hand Grips, Model: X20S Transmitter/X20S Transmitter with R8 Pro R9 MX Receiver & Hand Grips (Optional), Color: Blue/Black, Model: X20S, Weight: 2500g, Mode: Mode 2 (Left Hand Throttle), Brand Name: FrSky
Banggood ($494.99)
Banggood warehouse is located in China. There are no coupons for this product in Banggood. What about the price? From what I can see this price is higher than average price ($389.14).
Link: Banggood product page
Price: $494.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGRCRR9, BGCuponation10, BGRRCB10, BG4b88a7, BG6c08a2, BGc4bd33, BGaeeb43
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Do you need price history chart (for all/most countries) for FrSky Tandem X20S RC Transmitter? There we go.
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)).