Nothing wrong with the Bass Pro, Cabelas or similar rigs, and they will definitely be a step up from your old rig, but for $100 or less budget, I think that you can get a better setup if you build it yourself. If you aren't building it yourself, I'd definitely look at the Bass Pro or Cabela's stuff. Nothing wrong with them, and they will serve you well. With the advances in composite technology in the last 15 years, you should see a pretty large improvement with even the entry level stuff.
As far as building your own, I'm not label conscious, so I tend to try to maximize my performance for the $ I spend. For lower cost range, I really like Amtak, Forecast, and Tiger-Eye blanks. Mid-range is where the best value for the $ spent occurs. I would look into Rainshadow or DanCraft. They are great blanks at any price.
If you buy a kit from somewhere like Cabela's you are most likely getting regular chrome snake guides and an entry level seat, which is fine if that is what you want. It will take the hassle out of picking out everything you want on your rod, plus they usually come with finish, thread, and everything you need to get the job done. If you want ceramic fly guides, nicer seat, gold or black hardware, or a specific type of wood, you can pick out your own components for a similar price or slightly more depending on how much more your components cost than the entry level stuff.