Thanks for all the responses, guys.

I would mainly just use a bike for paved roads to go to the store. I
already have a cheap beater bike, a Magna that I use to go to the
stores with, usually about 2 miles one way and it takes me about 20
mins to do so. It's a inefficient bike, but still easier than a
Huffy. Bike riding has to be easier.

Someone here recommended a hybrid bike, and I believe that is an
excellent recommendation. The '08 Trek 7000 is just in my price range
too... Not more than $350. I'm going to a bike store soon.

I am 5'4" and about 130-150 lbs. What size bike am I looking for?