New and clueless BB Tour user

Forgive me for sounded dumb, but I'm new to the BB Tour. I've read about all the ringtone issues, which I'm also having. It doesn't seem like anyone has the answer to correct the problem for good.

My question is BB apps. Do I download them from my phone or on the computer? And, do they drain the battery even more? Are the apps a one time fee or do they charge monthly? Any recommendations on favorite apps to download?

Thanks for any and all help and recommendations