$41.99 – KINGBOLEN BM550 Car Battery Tester (Banggood, Aliexpress: KINGBOLEN BM520 Battery Tester For Car 6V 12V 24V Batter Analyzer Multimeter Cranking Charging Ripple Test (the best price with coupon)).
ATM you can buy KINGBOLEN BM550 Car Battery Tester for $41.99 (in Banggood). Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
Latest coupon code price check (UTC time):
Banggood ($41.99)
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood. I think you want to know if the price is good. Well, this price is higher than average price ($30.52)
Link: Banggood product page
Price: $41.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG68b373, BGSCM11, BGRJANBM52, BGAMMT03
(these codes were not working in latest coupon update, but you can check them out anyway)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for KINGBOLEN BM550 Car Battery Tester. The lowest price was: $29.04.
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)).