U7F-SZQ-SF7
I used the free trial and then didn't pay right away, and they just sent me a 30% off code, which seems to be generic. It looks like it works for both single purchase and subscription.
Note that this won't work if you install Parallels from the app store, you'll need to download the installer from the website.
Does anyone have any recent experience on how Parallels compares to Vmware Fusion?