Just check coupons out (with price alert and history). Best price?
Model P115K, Size L77xW25xH57mm, Output Type-C: 5V/3A /9V/2A;18W(Max), Capacity 9000mAh, Brand AWEI, Operating Temperature -10°C~50°C, Input Type-C: 5V/3A /9V/2A;18W(Max), Color Black, Energy conversion rate ≥ 75%, Name PD22.5W Quick Charge 9000mAh Power Bank, USB-A: 5V/2.4A /9V/2A /12V/1.5A(4.5V/5A;22.5W Max), Material Polymer Li-lon, Storage Temperature -20°C~60℃, Weight 170g
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):
Banggood
Banggood warehouse is located in Europe 
. Hmmm… There is no active coupon in Banggood at this moment. I don’t want to misguide you about the price. I don’t know if it’s good, because I don’t have enough records in my database…
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): BGf9cace, BG1efeb0, BG00c906, BGJUNEGSG9
(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 is not available for this item (not enough database records)! The lowest price was $16.99 though.
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)).