I’ve got an AWS free tier account for a year recently. The free should mean free of charge, but even before a month, suddenly I got an unpaid bill notification from Amazon.
By looking at above image, I saw that the bill comes from EC2 service, which I use it for setting up a VPS. After deep looking at the bill information, I got the culprit. It was the Elastic IP address that got me to pay the charge.
Briefly, I requested a static IP address to be associated to my VPS. I didn’t aware that the IP has to be bound to any instances. Once it is disassociated, we will be charged at per-hour rate. And unfortunately, I disassociated it for a few hours by unknown reason. As the result, I had to pay Amazon for $0.36.
So, instead of disassociate the ellastic IP address, we just have to release it. Perhaps it will be useful for other people.