With Amazon Elastic Block Store, you only pay for what you use. Volume storage is charged by the amount you allocate until you release it, and is priced at a rate of $0.10 per allocated GB per month.
This is priced per month. Other things are priced per hour (and that means that if you use something for two minutes, you still pay an hour).
So what if I allocate 10 GB at 8 AM every day, and deallocate it at 10 PM, so that at no time I am using more than 10 GB. Will I be charged for 10 GB or for 30 times 10 GB?
What if I allocate 100 GB, but only for one day? Will that be the same cost as having the 100 GB for the whole month, or just 1/30th of that?
I have been reading the FAQ and other docs for a while, but could not figure it out.
I’ve read the FAQ too but let me tell you that if Amazon charged me the $0.10 with a monthly rate I’d be broke by now. I spin up (and spin down) ebs-backed servers several times (30-40) a day and still receive a bill that is not much more than a few dollars.
My guess is that they charge you hourly and this question on serverfault seems to confirm that experience