Go to an apple store and try it out. The only easy and free thing I could reccomend that would be anything like OSX is kubuntu. I reeeeeeally would reccomend against that unless you know your way around your pc and what hardware is in it. I've played with unbuntu a bit, but you'll most likely be manually installing device drivers through the terminal unless you're lucky enough for it to find them or kubuntu isn't just a different interface like it says.
They do have a very large support forum, so if you have experience and and you're feeling like something new, go for it.
you may end up having to reformat your drive, so keep it in mind that if you have any information you want to keep, back it up.