OS Redmagic OS 2.0(Based on Android 9.0), Pixel Density 387.5 PPI, RAM 8GB LPDDR4X, Type AMOLED capacitive touchscreen, CPU Qualcomm Snapdragon 855, GPU Adreno 640, Brightness 430nit, Battery(Built-in) 5000mAh(Built in Polymer Battery), Display Size 6.65 Inch 19.5: 9 Oversized full HD Screen, Octa Core (1×2.84 GHz Kryo 485 & 3×2.42 GHz Kryo 485 & 4×1.80 GHz Kryo 485), 16M colors, ROM 128GB UFS2.1 2-LANE, Resolution 1080*2340 FHD+, Contrast 100000: 1.
Basically copy coupon, view price history or create e-mail price alert. Do you want to know what the best price is?
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 coupon and price update (UTC):
Banggood
Banggood warehouse is located in Hong Kong.
Link: Banggood product page
1. ($527.79): BGaDmITAd
2. ($534.99): BGNRM38
you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Price history and price alert
Price history (for all/most countries) for ZTE Nubia Red Magic 3 8/128GB Global Black is here. The lowest price was: $527.79.
Price records source(s): 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)).