According to my DB the lowest price is $9.99 for KWS-2301C Multi-function Digital Display DC Voltage Ammeter Power Meter (in Banggood). Basically copy coupon, view price history or create e-mail price alert. What is best price?
KWS-2301C Type-C Tester DC 4-30V Voltmeter Amperimetor Voltage Current Meter Ammeter Detector Power Bank Charger Indicator
Latest coupon code price check (UTC time):
Banggood ($9.99)
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood. Is it good price? Well, this price is higher than average price ($7.09)
Link: Banggood product page
Price: $9.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG160f8b, BG94c95c
(probably won’t work, but you can try them out)
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
Price history (for all/most countries) for KWS-2301C Multi-function Digital Display DC Voltage Ammeter Power Meter is here.
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)).