Type S210H, CPU Intel Core i9-9880HK, Hard Drives Capacity NO, Brand HYSTOU, Wireless 10/100/1000Mbps Ethernet, Display core Intel HD Graphics, Core Eight Core / 2.3GHz /Up to 4.8GHz, Bluetooth “Bluetooth(Depend on wireless module)
(PCIex1: M.2 22×30 (key E) slot)”, RAM NO, WIFI 2.4G or 5G Wifi B/G/N/ac, Type Mini PC.
Basically copy coupon, view price history or create e-mail price alert. Best price?
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 code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($429.99): BG50d083
2. ($739.29): 13f142
apply code in your basket (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): BGd7bd11
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for HYSTOU S210H i9-9880HK Barebone Mini PC is here. The lowest price was: $338.99.
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)).