"for school" is not very indicative. If you just mean surfing the web for research and writing basic papers and doing Powerpoints, you don't need a lot of power. With sales, you should be able to score a basic computer for under $400.
If you will be playing games, you'll want speed and memory, and if you will need any kind of editing software and be creating large, multimedia files, that's something else.
If you are taking the laptop to college, look into the security. Some have fingerprint logins and/or you can buy a lock for it. It will be a worthwhile investment. Finally, BACKUP--whether you store your work in GoogleDocs or the Cloud, or you buy an external drive, you'll want to safeguard anything that will devastate you to lose. Computers break at the most inconvenient times. Getting a $50 backup might save you from repeating a semester or a poor GPA.