What is a reasonable budget for a hybrid bicycle?

[wileywafer]

I'll be spending $800 on amazon hybrid bike that I want to use throughout my time in high school. I would use it to go to and from class, work, the supermarket, the mall, and other places. My old bike (purchased from Canadian Tire for $200) is broken, so I can't ride it. I considered having it fixed, but the cost would have exceeded the bike's worth by $100. To prevent this, I've been debating whether to invest in a better lock (at about $100) or a cheaper bike (around $500). I'm risking everything on this bike, and I'd hate to see it stolen or broken.