I have just checked coupons. The lowest price I could get is 15.99 USD for TS02A Pen (in Banggood). You can create price alert here, copy coupons and view price history. You probably want to know what is the best price?
Latest price update (UTC time):
Banggood (15.99 USD)
Banggood warehouse is located in China. I can’t find any active coupons for this product in Banggood. Isn’t it too expensive? Hmmm, price is higher than average (which is 10.49 USD right now), so better set price alert down below…
Link: Banggood product page
Price: 15.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGM1TOOLS88
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Aliexpress
Click here… to search for MESTEK TS02A Pen Type Multimeter on Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for MESTEK TS02A Pen Type Multimeter.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).