Look at the ladies equivalents of the Specialized Sirrrus, and the Trex FX, and many other manufacturers - it's a good time to be in the market for last years model.

Yes, you can find nice Performance Hybrids at your price point. Don't, automatically, turn your nose up at "mens" bikes, as many are the same as ladies, and many just might fit you better........

Like others, I recommend one that will accept racks and fenders (Planet Bike Hardcore Hybrid Fenders, are nice and affordable - and will keep both you and the bike cleaners and drier.) Also, 700 size wheels roll lots easier, especially if you keep lots of air in your tires.)

Oh yeah, don't forget a good lock, and know how to properly use it............... lots of bikes seem to go astray at school, you gotta make it difficult for them.