Q:

AWS EC2: how to compute the cost

i'm new to AWS, i'm using the free right not and it's terrific.
Now, in 1yr the free expires.
i went to the website http://aws.amazon.com/ec2/pricing/ where the pricing is but i didn't really get how to compute it.
The price are in $ per Hours but i don't think that this means, if i need to have my application running 24h/365d i've to multiplay it for 8760, or do i have?
because they write about usage, but how do i compute this value?
if i've a website where people in total spend smt like 10 minutes a month and 1 where people spend 750hour a months i pay the same?
i can't believe that is the same price.
PS:if i've a scheduled task, does it affect the usage?

A:

It is the same price. Yes, your calculation is correct; you are billed that amount for each hour in which the EC2 instance is running. How many people visit a web site whose pages you're serving out of that instance, or how much time they spend looking at those pages, are irrelevant to the cost calculation.
If you are buying an instance that should be running 24/7, and you have no need to run it intermittently or to add more instances on the fly at particular times, then perhaps you may also want to look into other hosting providers beside Amazon and the EC2 offering.  It's called "elastic" for a good reason! :)

