Just check coupons out (with price alert and history). Let’s see what best price is ATM.
GPD WIN Mini 7840u GPU 7inch Gaming Handheld GamePad Tablet Mini Portable Pocket PC Laptop Game Player Console – 64+2tb
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. I couldn’t find any coupon for this product on latest product update.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGBFDAY8, BGNEWYEAR8, BGHONEYSP
(there’s a little possibility that old coupon will work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – GPD WIN Mini 7840u 7inch GamePad 32/512GB ($-3)
Price history and price alert
Here is price history (for all/most countries) for GPD WIN Mini 7840u 7inch GamePad 64GB 2TB.
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)).