Rated Voltage: 5V = 1A, Product Model: YLFWD-0004/YLFWD-0005, Product Weight: About 300g, Executive Standard: GB 7000.1-2015, rated Power: 3W, Battery Capacity: 1800mAh, Operating Temperature: -10°C~40°C, Product Size: 82mmx 82mmx 95mm.
Go down and check coupons out. Remember to check price history if it is available. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($23.75): BGLED2203
2. ($25.10): Terence
3. ($25.37): BG00c906
apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BGdf6a60, ADMITAD2212, 2022ACTIESNL, BGc6e40e, BGc7850d, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, BGef16b1, Cuponation9, BG8ReviTrage, BGYEE2022, BG01ca42, BGLEDNOV2022
(there’s a little possibility that old coupon will work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Yeelight LED Rainbow Sunset Red Projector [EU] ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for Yeelight LED Rainbow Sunset Red Projector? There we go. The lowest price was: $20.99.
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)).