At the Build 2016 conference, Microsoft introduced the exciting news that Xamarin will now be available for all existing MSDN users at no extra cost.
Windows Developer
Xamarin is included in Visual Studio. Now you can develop mobile cross application using windows machine.
Mac Developer
MSDN subscription users can download Xamarin Studio for Mac machine, no need to pay any payment.
Step 1
Login to MSDN subscription.
Step 2
Click on Register and Download.
Step 3
Click checkbox on “I Agree" and click on “Subscribe” button.
Step 4
Now you can develop mobile cross application. Free Licensing will allow only one machine at a time.
If you want to use different machine, you want to disable previous machine licensing like below,
Step 4.1
Login to www.Xamarin.com
Step 4.2
Go to https://store.xamarin.com/account/my/subscription/computers
Step 4.3
Click on Deactivate and Enable different machine.