Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
Coupon (219.01 USD): 6GSGIT
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply 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): BGXMSRE1, 502C6B, BG238XM, AFfbG10, BG1108H, BG11111H, BGES1111XM, BGBFAFF2019, BGCITYADS2019, BGFR112607, BGXM2381, BGXMM813, BG75798, BG121XM23, BGGrupoReviews, BG7578, BGOX813, BGTT10, BGCZXM238, BGNAXMOM1, bGhOnEy10, BGXMCZ798, BGBDOSXM, BG75798CZ, BGXMCZ7988, bGhOnEy20, bgtt1010, 7d18f7, Email5, BGD75798, BGXM0721, BG721XP05, BGMX0721, BGBAN721007, bgshOOp10, BGOX8130, BGMP7980, BGDE2813, BGOX8131, BGOX8132, BGBM9907, BGXM9913, BGST9907, BGXM2813, BGXMW238, BGXM2313, BGHALLOWEEN, BGMST11, BGMST12, BGOMG11, BGRUZ798, BGXMC798, BGDOZ5, BGCE981, BGSTUDENT10, 13f142, BGCuponation10, BGES79831, BGRU75798, BGCZ798, BGES813, BG326YDL98, BGKD798, BGXBUSA30, BGXM30USA, BGXMUSA20, BGAUXM15, BGadff95, BG3da6aa, BGde660e, BG0fa9de, BG24e54a
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for Xiaomi 23.8-inch Computer Gaming Monitor is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).