Basically copy coupon, view price history or create e-mail price alert. What is best price?
Output Power: 4W, Holder: E27, 350 lm, Color Temperature or Wavelength: 2800 – 3200K, Lifespan: 50000h, Available Light Color: RGBW
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Price history and price alert
Price history (for all/most countries) for Utorch Magic Blue UU E27 RGBW LED Bulb is here.
Price records source(s): Gearbest
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)).