If you've already configured your local machine's PowerShell environment to interact with your Azure subscription (see here: http://www.windowsazure.com/en-us/documentation/articles/install-configure-powershell/), then you can begin saving yourself an awful lot of button-clicking by scripting out the start/stop of your VMs, especially if you have a cluster of Azure VMs for testing and demonstrating SQL Server Availability Groups, as an example.

You will need to change a few things in these scripts to suit your purposes:

1. Change "YourAzureAccount@hotmail.com" to your Azure account. For MSDN-based Azure subscriptions like mine, this address was my Hotmail email address.
2. Change "Visual Studio Premium with MSDN" to the name of your Azure Subscription. This was the name my MSDN-based account was given by default.
3. Populate the $vms variable with a list of Azure VM's in the cluster you're looking to start/stop as a group, replacing "yourVMName-alwayson-dom" and so forth.

Big thanks and credit for the assist on this blog post to Cody Gros, SharePoint Solutions Architect and my coworker at Sparkhound.

Stop a list of Azure Accounts:

#if expired, Add-AzureAccount

Get-AzureSubscription | ? {$_.ActiveDirectoryUserId -eq 'YourAzureAccount@hotmail.com' -and $_.SubscriptionName -match "Visual Studio Premium with MSDN" } | Set-AzureSubscription -SubscriptionId $_.SubscriptionID

$vmHash =@{}
$vms = "yourVMName-alwayson-dom","yourVMName-alwaysonsql1","yourVMName-alwaysonsql2","yourVMName-alwaysonWSFC"

Get-AzureVM | foreach{$vmHash.Add($_.Name,$_.ServiceName)}

foreach ($vm in $vms) {    
    $currentVMService = $vmHash[$vm] 
    Write-Host "Current VM:$($vm)"
    $thisvm = Get-AzureVM -ServiceName $currentVMService -Name $vm
    Write-Host "Stopping VM:$($thisvm.Name)"
    Stop-AzureVM -Name $thisvm.Name -ServiceName $thisvm.ServiceName #-StayProvisioned  
}

Note about the -StayProvisioned tag above. Specifying this option will retain some IP settings, but will cause your VM's to continue to accrue Azure credit, even while stopped.  Use with care.

Start a list of Azure Accounts:

#if expired, Add-AzureAccount


Get-AzureSubscription | ?{$_.ActiveDirectoryUserId -eq 'YourAzureAccount@hotmail.com' -and $_.SubscriptionName -match "Visual Studio Premium with MSDN" } | Set-AzureSubscription -SubscriptionId $_.SubscriptionID

$vmHash =@{}
$vms = "yourVMName-alwayson-dom","yourVMName-alwaysonsql1","yourVMName-alwaysonsql2","yourVMName-alwaysonWSFC"

Get-AzureVM | foreach{$vmHash.Add($_.Name,$_.ServiceName)}

foreach ($vm in $vms) {    
    $currentVMService = $vmHash[$vm] 
    Write-Host "Current VM:$($vm)"
    $thisvm = Get-AzureVM -ServiceName $currentVMService -Name $vm
    Write-Host "Starting VM:$($thisvm.Name)"
    Start-AzureVM -Name $thisvm.Name -ServiceName $thisvm.ServiceName    
}

If upon running the scripts you receive either of these errors:

get-azuresubscription : The term 'get-azuresubscription' is not recognized as the name of a cmdlet, 

Get-AzureVM : The term 'Get-AzureVM' is not recognized as the name of a cmdlet, function, script file, or 

Then you don't have the PowerShell module loaded, and PowerShell isn't automatically loading it for you. Use the Import-Module command. Below is the default location of the module.

#if expired, use Add-AzureAccount
Import-Module 'C:\Program Files (x86)\Microsoft SDKs\Windows Azure\PowerShell\Azure\Azure.psd1'