We’ve previously covered storage costs and bandwidth costs which are two of the three overly complicated components that make up an S3 storage bill. Storage and Bandwidth make up the vast majority of most monthly bills but there is a third, much smaller component that they call “Request Pricing”. Amazon defines “requests” as POST, COPY, PUT, LIST and GET requests.
PUT, POST and LIST requests are involved in uploading files while GET requests occur while downloading files.
PUT, COPY, POST, or LIST Requests are $.01 (one cent) per 1,000 requests while GET requests are $.01 (one cent) per 10,000 requests.
Each of these happen quite often when transferring data to and from your account but the costs for these requests are extremely small. So, unless you’re running a production type service from your S3 storage these requests should make up only a very small portion of your bill. In my bills these components have never exceeded $.01 (one cent).
You can get great, albiet highly technical definitions of PUT, POST, and GET requests on here on Wikipedia.