I think that you should be looking for a real bike shop. It might take a few tries to find the "right" one.

What you should be looking for is a sales person who asks you the "right" questions about your lifestyle and how you picture yourself using your new bicycle. There are lots and lots of bicycle variations and working through those questions will steer you toward the best style of bike to suit your needs.

The next thing is "fit". Your position on the bike affects your comfort, efficiency and performance every single minute that you're on the bike. Compared to fit nothing else even comes close in importance. The good folks at Dick's might not be the kind of bike enthuiasts that can help you with fit.

Your budget will drive everything else so there's no point in worrying about it.