Basically copy coupon, view price history or create e-mail price alert. Best price?
Global version (B20 LTE Support, Global MIUI version), 6GB RAM 128GB ROM MIUI 8 or Above 5.7 inch 3D Curved Glass Screen Snapdragon 821 Quad Core 8.0MP + 22.56MP Cameras Type-C Bluetooth 4.2 NFC 4070mAh Battery
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 code price check (UTC time):
Price history and price alert
There is only one database record (it was for $339.99), so you can’t see price history chart.
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)).