You can get LH351B Flashlight with for 18.99 USD using coupon code (in Banggood). You can create price alert here, copy coupons and view price history. What is best price?
Latest coupon code price check (UTC time):
Banggood (18.99 USD)
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood. Well, is it a good price anyway? From what I can see this price is higher than average price (15.90 USD).
Link: Banggood product page
Price: 18.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGBFD160, BGd57765, BG49aefb, FIN3356
(these coupons are old, so probably won’t work)
Aliexpress
Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for Astrolux EP03 2050lm LH351B Flashlight with Batt is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).