You can get 12-24V Triple USB Car Charger for $7.99 with coupon (from Banggood). You can create price alert here, copy coupons and view price history. Best price?
12-24V Triple USB Car Charger Socket QC3.0 & Two PD3.0 With ON/OFF Independent Switch Fast Charging Adapter – Blue Light
Latest coupon code price check (UTC time):
Banggood ($7.99)
Banggood warehouse is located in China. Too bad there’s no coupon right now in Banggood. But wait a sec… Is it a good price? This price is higher than average price ($7.49) for this item.
Link: Banggood product page
Price: $7.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGAMMT03
(these coupons are old, so probably won’t work)
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 12-24V Triple USB Car Charger 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)).