What kind of bike would be good for me?

Do not get a bike from Walmart! The only advantage is that no college kid with a brain and decent self-concept would steal it! I'd also stay away from hybrids. I think that you may end up enjoying biking and wanting to continue the sport for exercise one day, and this means needing a road bike. Entry level road bikes will cost you more than $300, but in the long run, the amount you spend will still be far less than the $600 a year you'd spend on parking. If you dont have hills to contend with, single speed commuters are a good option, just make sure you ask your bike shop if the gearing is appropriate for your skill and the terrain. A single speed will last longer (fewer components to break) and you could own it until your my age! I am 37 and ride a variety of bikes. My single speed from 12 years ago is now my baby courier! Good luck and have fun.