ATM you can buy TX16S Mark II for 312.79 USD (in Banggood). Just check coupons out (with price alert and history). What is the best price?
Latest price update (UTC time):
Banggood (312.79 USD)
Banggood warehouse is located in China. The question is – is it a good price? From what I can see this price is higher than average price (259.11 USD). There is one great coupon!
Link: Banggood product page
Price without coupon: 339.99 USD
Coupon (312.79 USD): BGHONEYSP
(CouponsFromChina.com tip: coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): 8BGwbg2204, BGRCParts8, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, hoNEYbGdeAlS, BGToys1, BGRCT10, BG48851e, BGJUNEGSG9, BGRADIORU, BGToys8, JanBGCoupon8, BGSaleFeb8, BGSaleAD, BGMatt2022, BGMARCHSALE, BGRA7715, BGAUGUST8, BGCAPITALOS8, BGCOUPERT8, BGBFDAY8, BG6c8014, BGNEWYEAR8, BGSPRING8OFF
(these codes were not working in latest coupon update, but you can check them out anyway)
Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for RadioMaster TX16S Mark II MAX V4.0 4-IN-1 ELRS RC Controller.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).