$12.69 – 4.2A Waterproof Car 2 Port Dual USB Charger Socket Power Outlet with LED Voltmeter for 12-24V Car Boat Marine ATV Motorcycle – Blue.
I have just checked coupons. The lowest price I could get is $12.69 for 4.2A Waterproof Car 2 Port Dual USB Charger (in Banggood). Go down and check coupons out. Remember to check price history if it is available. What is the best price?
Latest coupon code price check (UTC time):
Banggood ($12.69)
Banggood warehouse is located in China. I don’t think there is an active coupon right now – at least in my database. But wait a sec… Is it a good price? Hmmm, price is higher than average (which is $10.11 right now), so better set price alert down below…
Link: Banggood product page
Price: $12.69
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BGSCM11, BGCAR639, BGAMMT03
(these codes were not working in latest coupon update, but you can check them 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 4.2A Waterproof Car 2 Port Dual USB Charger. The lowest price was: $7.59.
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)).