You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Resolution 1080*2340 FHD+, CPU Qualcomm Snapdragon 855, Type AMOLED, RAM 6GB, up 2.84GHz, 5000mAh(Built in Polymer Battery), GPU Adreno 640, OS Redmagic OS 2.0(Based on Android9.0), Octa Core, Display Size 6.65 Inch 19.5: 9 Oversized full HD Screen, ROM 128GB
Aliexpress
There’re some similar (or not) items on Aliexpress
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. ($464.99): od7off
2. ($469.99): affiliate6
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): BGRM36, aff7off, bgssaff9, BGKtechredmagic
(these coupons are old, so probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for ZTE Nubia Red Magic 3 6/128GB? There we go.
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)).