OLAF 5V 3.1A Dual USB Car Charger (Banggood, Aliexpress: 5V/2A (the best price with coupon)).
Get coupons, create price alert or check price history out! What is the best price?
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Price history and price alert
Check out price history chart (for all/most countries) for OLAF 5V 3.1A Dual USB Car Charger. The lowest price was: $1.29.
Price records source(s): Gearbest
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)).