Cracking password-protected zip files

I need some help with this, I got a zip file that won't allow me to extract the files (mp3s) in it unless I know the password, and the only way to get the password is for me to buy it online, which I don't feel like doing. I've looked all over the net for programs, and tried a lot of them, but most of them never were able to find the password for me in a bunch of possibilities. And I can't really find any program that allows me to delete or crack the password directly without searching through billions of possibilities.

Any suggestions or programs you can link me to?

That sounds rather illegal to me.

Have a pleasant day doing the (preferably legal) stuff you do.