$11.99 – Test voltage range: 0.1-230V/50-1kHz(EU/UK), Weight: 96g, Plug Standard: EU/UK/US Plug, Power: 1.5V (AAA)x 2, GFCI work voltage: 150V±20V, Work voltage: 2.6-3.3V, 0.1-150V/40-1kHz(US), Size: 65x65x61mm, Rated residual operating current: 5mA.
When I was updating this page, then coupon price was $11.99 for BSIDE ZT-E8 LCD Socket Tester (in Banggood). Check coupons or create price alert down below. Best price?
Latest price update (UTC time):
Banggood ($11.99)
Banggood warehouse is located in China. Hmmm… There is no active coupon in Banggood at this moment. Price? It’s a good price, isn’t it? The average is $12.36.
Link: Banggood product page
Price: $11.99
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG01031e
(I don’t think these’re gonna work, but you can try ’em out anyway)
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
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 BSIDE ZT-E8 LCD Socket Tester. The lowest price was: $9.99.
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)).