Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in Hong Kong.
Link: Banggood product page
Coupon (599.99 USD): BG7P401
Coupon (812.99 USD): Email5
(CouponsFromChina.com tip: this code has to be applied 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): BGOP7PRO8G, BGOP7PRO1, affiliate6, BGOP7PROB, BG7PROERU, BGOP7PRO, BGOP7PRO629, aff7off, BGOP7P73, BGletni17pro, BGOP7P79, bgssaff9, BGONEP7P, BGOP7P, bgop7pa8, BGOP7PUIJ, od7off, BGOP7pro654, BGOP7P298, bguijop7p, bg92op7p, BGaDmITAd, BGOP7P899, BG99OP7, BG99PRO7, BGOP7PGR8, BGTYOP7P8, 7bcdf9, BGOP7PGRU8, BGOP7PGRTU8, BGOP7C8, BGD11OP7P, BGBFAFF2019, BG11OP7P8, BG3COP7P8256, BGCITYADS2019, BGBFOP7P8, BGBF7T8256
(there’s a little possibility that old coupon will work)
Price history and price alert
Do you need price history chart (for all/most countries) for OnePlus 7 Pro 8/256GB Global ROM Gold? There we go.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).