As Ramhound stated, you can get VM's at no cost from Microsoft. They are available from the Modern IE website and they have everything from IE6 on XP to IE11 on Win8.1.
They have these VMs available to run on Mac (VirtualBox, VMWare, Parallels) and Linux (VirtualBox) in addition to Windows (VMWare, VirtualBox, Hyper-V and VirtualPC).
EDIT:
A good alternative that I use in my development is BrowserStack. Requires a subscription, but they handle all the VM stuff for you and you can test some mobile and tablet browsers (stock browsers for Android, iPhone, iPad, & Kindle Fire) as well as the stock desktop group.