You can create price alert here, copy coupons and view price history. What is the 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
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): TECH8%, d138f1, PICODICOM, BGXGLune4K, BGaDmITAd
(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
Do you need price history chart (for all/most countries) for XGIMI Lune-4K Projector? There we go.
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)).