Wow, Affinity looks pretty capable, I think worth trying out.
Still, no real alternative for video editing...
Davinci Resolve is also getting better over time. Some people say it's already good enough for them to use daily, I think it's too buggy.
You can copy the application (or airdrop) to any other Mac and it will work without and activation process or anything like that.
If $300 is a lot of money for your video editing software then you aren't the target market for software like this anyway. People at my school only have FCPx or premiere because of student discounts or because the school paid for it.