Infrared, Fingerprint Sensor, Ambient Light Sensor, 2340x 1080 FHD+ Corning Gorilla Glass 5 Screen, Google Play Store: Yes ，, GPRS, E-compass, Sensor: Accelerometer, Face ID, Bluetooth: 5.0, Gyroscope, Ultrasonic, Camera: 48.0MP + 12.0MP + 16.0MP rear camera + 20.0MP front camera, Gravity Sensor, A-GPS, wake gesture, GPU: Adreno 640, RAM + ROM: 8GB RAM 128GB ROM, CPU: Qualcomm Snapdragon 855 Octa Core 2.84GHz, Display: 6.39 inch, Beidou, Language: Multi-language, SIM Card: nano SIM card + nano SIM card, System: MIUI 10 (Android 9.0), Glonass, Feature: GPS, smart gestures.
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Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($573.29): BGaDmITAd
2. ($585.89): od7off
3. ($592.19): affiliate6
apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG6M9T, aff7off, bgssaff9
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Mi9 Transparent 8/128GB CN Black. The lowest price was: $573.29.
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)).