Aws pricing doubts (s3, glacier and dynamodb)

Im studing aws pricing and I have some doubts.

About Amazon S3, it says that we pay $0.03 per gb per month. But for example If I use only 256kb of storage, 256kb = 0.000256gb, using AWS S3 calculator it says that the cost is $0.00. So for small amounts of storage is always free??

And I have my s3 bucket configured with glacier class, so when I store this 256kb of data in s3, after 1 day this data is stored in glacier. So in this case, using 256kb for a day in s3 and then store in glacier, I dont pay nothing for s3 and glacier?

And also about Amazon S3 it says that we pay for get requests and for data transfer out from Amazon S3 To internet, If I acess for example a file inside my bucket from for example this link: http://ift.tt/1FOKKfk, it is a get request or data transfer out from Amazon S3 to internet??

And just one more about dynamoDB, it says that first 25GB stored per month is free, it is always free? Or it is just free for free tier?