I have just checked coupons. The lowest price I could get is $7.99 for 4-24V 1.5A Adjustable Power Supply (in Banggood). Basically copy coupon, view price history or create e-mail price alert. What is best price?
4-24V 1.5A High Power Adjustable Power Supply Regulating Voltage And Speed Switching Power Supply Temperature Dimming Adapter EU/US/UK/AU – EU Plug
Latest price update (UTC time):
Banggood ($7.99)
Banggood warehouse is located in China. I don’t think there is an active coupon right now – at least in my database. Good or bad price? This is the best price in history according to CouponsFromChina database!
Link: Banggood product page
Price: $7.99
This is the best price ever noted in my database!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
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
Do you need price history chart (for all/most countries) for 4-24V 1.5A Adjustable Power Supply? There we go.
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)).