What version of OS X are you running?
If you look to Amazon, you can find older versions of Final Cut that will work on your Mac and OS X version.
Another alternative is to find the version of iLife that had the iMovie version called iMovie '06 HD.
This version of iMovie is THE BEST EVER version of iMovie Apple ever developed.
Try finding this on Amazon, too!
Here's iLife '06 here on Amazon U.S.
http://www.amazon.com/Apple-iLife-Mac-DVD-VERSION/dp/B0007LW22G/ref=sr_1_1?ie=UT F8&qid=1396596220&sr=8-1&keywords=iLife+%2706
This is what you need to find.
If you are running OS X 10.6 Snow Leopard, this will run on that OS X version.
I use both this iMovie version as well as Final Cut Express on Snow Leopard.