Just check coupons out (with price alert and history). What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
10000mAh, Bidirectional quick charge, Double input ports with Type-C and Micro USB interface, Material: ABS, Model: ZMI QB810
Price history and price alert
Do you need price history chart (for all/most countries) for Xiaomi ZMI 10000mAh Power Bank? There we go.
Price records source(s): Gearbest
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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)).