Aliexpress
Click here… to search for Cheerlux CL770 1080p Projector on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (213.17 USD): BGPROBuscape
Coupon (225.71 USD): BGAProjector
(CouponsFromChina.com tip: apply code in your basket (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): BGCE607, aff7off, BGaDmITAd, BGCL607, BGBFAFF2019, BGCITYADS2019, bGpAnDacHeCk, Wholesale20, Email5, bGhOnEy10, BGdragonBoat, BGAFF7OFF, bgshOOp10, BgoFErTaSchInA10, BGAFF10OFF, 7bcdf9, BGProjectors
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for Cheerlux CL770 1080p Projector is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).