I've stolen over $400 from my school
Why did you steal that much money from your school?
Because I wanted to buy things I can't afford to buy.
I know that you want to buy things you can't afford right now but stealing from your school is wrong. You can't steal money that doesn't belong to you. If you want to buy something you need to earn the money honestly.
Damn, I regret stealing that money. But I'm enjoying my expensive shirt...
You should return the shirt and get the money back. You can get the shirt after you get a new job.