Aliexpress
Click here… to search for D40 Laser Distance Meter 40m on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (21.03 USD): BGherra
(CouponsFromChina.com tip: you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): 0e7f33, FBCOUPON1
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for D40 Laser Distance Meter 40m.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).