Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. I found coupon for you. Check this out.
Link: Banggood product page
Coupon (1709.99 USD): BGProj
(CouponsFromChina.com tip: you should apply the coupon 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): BG1f7712, BGAProjector, BGHU1958, BGbdb727, BG659ceb, BGprtecmundo, BGAudioVideo
(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 (for all/most countries) for Xiaomi Full Color Triple Laser Projector LCOS is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).