Ideally, I'm looking for free or low-cost solutions... I'd like to test out a variety of operating systems (windows, linux, mac os, etc).
Any help is appreciated!
You basically have three options for Virtualization on Mac OS X:
Any of these will allow you to run a variety of OSs under OS X without resorting to bootcamp or repartitioning.
The last two are not free, but -depending upon your needs- vastly superior in terms of features to VirtualBox. I have the three. I have used the three extensively. In its current versions, Parallels is ahead of VMware. But this changes very often with new versions. Virtual Box is ok but slower (to virtualize) and has way less features.
VMware is very stable. It never crashed in more than three years of daily usage. Parallels does perform certain tasks faster than VMware, but will occasionally crash the VM. (It happened about 5 times in a two year period).
In the end, either will work if you don’t need anything fancy.
You could try VirtualBox.
From its webpage :
VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers, it is also the only professional solution that is freely available as Open Source Software under the terms of the GNU General Public License (GPL).
Presently, VirtualBox runs on Windows, Linux, Macintosh and OpenSolaris hosts and supports a large number of guest operating systems including but not limited to Windows (NT 4.0, 2000, XP, Server 2003, Vista, Windows 7), DOS/Windows 3.x, Linux (2.4 and 2.6), Solaris and OpenSolaris, and OpenBSD.
VirtualBox is being actively developed with frequent releases and has an ever growing list of features, supported guest operating systems and platforms it runs on. VirtualBox is a community effort backed by a dedicated company: everyone is encouraged to contribute while Sun ensures the product always meets professional quality criteria.
I'm using it since I realise I didn't have to pay for having a good virtualization software on Mac OS X.
I can tell you it works really well, it's easy to setup and very stable.
You could also consider using bootcamp to partition your hard drive to run different operating systems.
Although you need to reboot to switch OS's I find that one advantage is it runs faster since it isn't being run as a program inside the Mac OS.
You can also use those same partitions when using Paralles which is a good vm software, however it isn't free.
Clearly it's not free, but if you're a professional who NEEDS access to various flavors of operating systems for your daily work, VMware Fusion is absolutely worth every single penny you spend on it. I'm a web developer, and even though most of my work is built in OS X, I'm constantly testing websites and webapps in IE 6-8, and being able to run separate instances of Windows XP and 7 at the same time has saved me so much effort and time that I can't even begin to describe it.