Final Cut Pro won't work with High Sierra

I upgraded to High Sierra today and of course in typical Apple fashion was not notified that Final Cut Pro would no longer work. As I tried to open Final Cut Pro, I got a message "the version of Final Cut Pro installed on this Mac is not compatible with macOS High Sierra. Download the latest version from the app store." But, when I click on the app store, they want $299 for the upgrade. This doesn't seem right. Isn't there a free upgrade that's compatible? Or am I screwed and have to pay for another version of FCP?