Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
Memory DDR4 8GB×1 Dual channel (SODIMM Slots×2), System Windows 10 Pro, Brand Minisforum, Processor “AMD Ryzen™ 5 3550H / 4 Cores/ 8 Threads
(Total L2 Cache 2MB / Total L3 Cache 4MB / Base Clock 2.1 GHz / up to 3.7 GHz)”, Storage M.2 2280 256GB PCIe SSD, GPU Radeon™ Vega 8 Graphics (Graphics Frequency 1200 MHz), Model DMAF5, Wireless Connectivity M.2 2230 WIFI Support (Intel® WIFI6 AX200 / BT5.1 pre-install), Storage Expansion 1×2.5 inch SATA HDD Slot (SATA 3.0 6.0Gb/s), Type Mini PC
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. ($419.99): BGdf438d
2. ($419.99): BG57f9c0
3. ($429.99): BG8cee08
put item in your cart and apply coupon code there 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
Price history and price alert
Check out price history chart (for all/most countries) for Minisforum DeskMini DMAF5 Ryzen5 3550H Vega8 Dual 8/256GB Mini PC.
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)).