Graphics Chipset: ADM Radeon RX 570, Process Technology: 14nm, Engine Clock: 1244MHz, CUDA Cores: 2048, Video Memory Frequency: 7000MHz, Video Memory Capacity: 4GB, Memory Bus Width: 256Bit.
Just check coupons out (with price alert and history). Best price?
Aliexpress
I could not find it 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. ($416.69): bGhOnEy10
2. ($416.69): BGHALLOWEEN
put item in your cart and apply coupon code there 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): 03db6d, e2bcea, TTxBG10, 2019SPEDM, AFfbG10
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Yeston Radeon RX570 4GB Graphics Card is here. The lowest price was: $199.99.
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)).