Mac OS X Tiger to Snow Leopard

Hello all,

I would really like to update my OS to Snow Leopard, but I notice that since I have Tiger it says to get the Mac Box Set. It talks about it have iWork and iLife, but I don't use all but maybe one of those programs. I don't really want to spend the money on something like that when I don't use it.

My question is - do I need to purchase the Mac Box Set to update my OS or can I do it by just purchasing Snow Leopard? If I do the second, will this mess up my computer in any way?

Also, will upgrading to Snow Leopard mess up any of my applications? How would I know?

Thanks for any and all your help!