Get the number of containers
(Get-AzureStorageContainer).Count
Get the number of blocks in the container
(Get-AzureStorageBlob -Container "ContainerName").Count
Not sure if you want the file size for each individual file or its size.
Get-AzureStorageBlob -Container "ContainerName", Length . Length - .
,
Get-AzureStorageBlob -Container "ContainerName" | %{ $_.Length } | measure -Sum
, ,
Get-AzureStorageBlob -Container "ContainerName" | where { $_.LastModified -gt (Get-Date -Date "specific date") -and $_.LastModified -lt (Get-Date -Date "specific date") }