You can get BSIDE S30 Smart for 35.99 USD using coupon code (in Banggood). Basically copy coupon, view price history or create e-mail price alert. Best price?
Latest coupon and price update (UTC):
Banggood (35.99 USD)
Banggood warehouse is located in China. There are no coupons for this product in Banggood. What about the price? This price is higher than average price (34.79 USD) for this item.
Link: Banggood product page
Price: 35.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGTOOS729, BG8FORMULAMX
(you can check these old coupons out, but these probably won’t work)
Aliexpress
Click here… to search for BSIDE S30 Smart Multimeter on Aliexpress
Here are coupons that you can use.
Price history and price alert
Check out price history chart (for all/most countries) for BSIDE S30 Smart Multimeter.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).