Battery 3x 1.5V(AAA) (Not included), Product size 163mmx 55mmx 28mm, Product weight 118g, Working environment 0~40° C (≤80%RH), 40~50° C (≤45%RH), Full battery duration >12hrs with bluetooth function on, Storage environment -20~60° C (≤75%RH).
Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the 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 and price update (UTC):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
1. ($32.21): BGGines
coupon code has to be applied in shop’s 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/i1u
Old coupons (from the oldest to the newest): 0e7f33, FBCOUPON1, BGherra, Tabby20
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for UNI-T UT383BT Bluetooth Luxmeter. The lowest price was: $20.6.
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)).