Just check coupons out (with price alert and history). Best price?
6GB RAM, 128GB ROM, Global, Black
Aliexpress
There’re some similar (or not) items on Aliexpress
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 Hong Kong.
Link: Banggood product page
1. ($189.00): BGRN9SPD
2. ($199.00): BGGMN9S
coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGMMF402, Email5, BGN9S128, BGN59S128, BG5N9S128, BGX9S8ES, 7d18f7, BG79S200, BG7N9S, BG7N9S128, BG8N9S6, BG8N9S6JP, BG8RN9S6, BG9N9SANN, BG16R9N9S, BG11N9S6, BGD11N9S, BGD11N9S128, BGDON9S128, BGWPN9S128, BGDBFN9S, BGBFIFN9S2, BGBFN9128EE, BGBFN9128UK, BGBFN9128ES, BGBGLTN9S128, BG12N9S, BG12N9SS, BGGMN9S100, BGBR01N9S, 13f142, ADMITAD2212
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Other warehouses/versions
This item is available in 2 another warehouse/versions!
1. Hong Kong – Xiaomi Redmi Note 9S 6/128GB Global Special Version ($-3)
2. Europe – Xiaomi Redmi Note 9S 6/128GB Global [EU] ($-3)
Price history and price alert
Price history (for all/most countries) for Xiaomi Redmi Note 9S 6/128GB Global is here.
Price records source(s): Gearbest, 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)).