Feel free for anyone to correct me if I'm wrong, but I think no matter how long you have had the NFL app you will be charged for the video content that is on there, the app itself is always free.(that's according to comments I've read on the market about the app).
But there are a couple way's to back up your apps, the easiest and free way to do it if you are unrooted is to use astro file manager. The downside to using this method is that you won't get notifications about when an update is available for the apps you've reinstalled with it, and will have to manually update/download them again through the market if you want to receive updates. Another way is to set up an account with app brain. App Brain basically keeps track of all the apps you have on your phone, but after you do a factory reset, you will still have to manually download and install your apps again. If you are rooted, the best way is to use Titanium Backup, it will not only back up your apps but also data that might go along with it, and all apps can easily be automatically restored(in the paid version, manually have to validate each install in the free version). The paid version will also re-sync your apps with the market so you receive update notifications. In my opinion the best way to do it is to use app brain and just do a fresh install of all your apps, there is less chance of any issues, or if you are rooted, use the paid version of Titanium Backup(it is worth more than what the developer charges. I have also heard of people using another app called backup pro with decent results.
edit:just an FYI, the new update for flash in the market might fix your browser lag issue.
