Or for a lot more?
IT Wire has a good introductory article about VirtualBox.
Sadly their introduction is a bit wrong in the details, as VirtualBox obviously is not “the only professional virtualisation solution that is freely available as open source software under the GNU General Public License (GPL.) Why this matters is because it’s truly free, as in freedom.”
Amongst others Xen is also fully GPL, and given its backing from both Citrix and most of the major Linux vendors it’s also professionally supported.
Also it also isn’t the only one that can run unmodified guests , both KVM and Xen can do this, given the these days standard VT hardware support. VirtualBox however does not need VT support (and neither did Qemu).
However, it’s still a fairly good introduction and keeping these remarks in mind it’s a good read, and it shows that VMWare should watch its back, and not just for VirtualBox