I just want something for riding around town, probably no more than 5 miles each way.
Well, that sure isn't going to add up to much exercise. Still, in that price range, I wouldn't expect a bike to stand up to a lot of riding.
What you REALLY need to do is this: 3 times a week, 30 minutes of vigourous exercise. Even on a comfort bike, this would equal at least 10 miles. Fast walking is also a good place to start-even in the cold.
chances are, if you start riding regularily, you will soon find the limitations of a hybrid, and will look for something better-so don't blow a lot of $$ on a hybrid.
As far as gyms go-forget the ones that require annual contracts-you won't feel comfortable around that crowd, anyway. A local Y is a good idea, or even some towns have community gyms. I work out at the gym at my
alma mater, and only have to pay $180/ year for the privilege.