Xiaomi Redmi S2 4/64GB Global Gray (Banggood, Aliexpress: 5.99 inch, MIUI 9, Qualcomm Snapdragon 625 Octa Core 2.0GHz, 4GB RAM, 64GB ROM, 12.0MP + 5.0MP, Rear Camera, Fingerprint Recognition, 3080mAh Built-in, Global Version (the best price with coupon)).
You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
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. One coupon is available. Cool!
Link: Banggood product page
1. ($154.69): BGaDmITAd
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 9BGS2649BGS264C9BGS264CL2, 10BGS264C11BGS264, bgssaff9, aff7off, BG9S2, 9BGS264GB, 10BGS264CL, BGESS23, BGESS2, BGESS3, 7bcdf9, BGESS4, BGESS5, BGBFAFF2019
(these coupons are old, so probably won’t work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Xiaomi Redmi S2 4/64GB Global Gray [EU/ES] ($-3)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Redmi S2 4/64GB Global Gray. The lowest price was: $125.99.
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)).