Just check coupons out (with price alert and history). Best price?
HDR10 Decoding Technology, Native 4K HD (3840×2160), Motion Compensation, Newest TI Dual DLP Technology, Laser Projector Technology, 60W Harman/Kardon HiFi Stereo, Brightness 2200 ANSI Lumens, P3 Ultra-Wide Color Gamut, Super Short Focus
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($2789.07): aff7off
2. ($2789.07): bgchinafest
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): TECH8%, d138f1, PICODICOM, BGXGLune4K, BGaDmITAd
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for XGIMI Lune-4K Projector is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).