wanted: road bike in decent condition

I am looking for anything that will get me a few miles to lab and back every day--preferably something crappy enough not to steal (old is fine if it's in halfway decent condition) but not a "walmart brand" that is going to break or already has broken. Looking to pay ~100$ but will consider up to $200. Mountain bikes might work, too. I'm a 6'1" male but am open to riding almost anything. Thanks for your help!