Unless your high school provides Windows 10 to it's students, you won't be able to get the education version. Just like everything else in life, Windows costs what it costs. If you can't afford it, you don't get it.
Fortunately, Microsoft has softened things up and what to get most people over to Windows 10. You can legally download and run Windows 10 directly from Microsoft without activation. There are some very minor restriction (no personalization) but I know people who have run Windows 10 this way for well over a year without issue.
https://www.microsoft.com/en-us/software-download/windows10
Go here and use the Media Creation Tool to get a LEGAL copy of Windows 10. During the installation, when it asks you for the product key for activation, you should have an option that says something like, "skip for now" and the install will continue without issue.
-Wolf sends