Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (735.33 USD): Email5
Coupon (735.33 USD): bgshOOp10
(CouponsFromChina.com tip: apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): affiliate6, aff7off, bgssaff9, od7off, BGaDmITAd, 7bcdf9, BGBFAFF2019, BGCITYADS2019, BGMPB2020
(probably won’t work, but you can try them out)
Price history and price alert
Do you need price history chart (for all/most countries) for HUAWEI P30 8/64GB Black? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).