If you use FL Studio, it has something of the sort built right in called "ZGameEditor". Personally, I find it kind of hard to work with though... not that I've spent much time with it... But regardless of ease of use, it has some pretty cool effects in it that react to your music.
That aside, the most common (I dare say) visualizer you probably see people use on youtube for song uploads is the one that comes stock with Adobe After Effects. Which of course you need After Effects to use... and like the rest of Adobe's products.. I don't think it's cheap.
I'm sure you could probably find free alternatives out there somewhere... but I, unfortunately, do not know of any.