Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
| Image | Product (link) | Price | Coupons |
|---|---|---|---|
 |
2M DC 5V 5.5×2.5 / 5.5*2.1mm Connector Power Cable for Beelink GT1 Ultimate TV Box Routers Digital Cameras and More Devices … | $9.83 | – |
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Amlogic S912 Octa Core CPU Android 6.0 Bluetooth 4.0 Media Player
Price history and price alert
Price history (for all/most countries) for Beelink GT1 Ultimate TV Box is here.
Price records source(s): Gearbest
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)).