Why can't I download apps from the App Store on my iPhone 4S?

I've had my iPhone 4S for about a year and have never had any problems. I'm trying to download some free apps, but when I click the install button, it looks like it's about to install. Then it suddenly stops. I don't know what's going on! I tried updating all my apps, and when I got down to the last 2, I couldn't update them either.
I'm up to date with my software, I don't have any unpaid bills for the App Store, and I've tried resetting the phone twice. Nothing has worked. Anyone have any advice?

It could possibly be an App Store glitch because I've been having the same problem in the last couple of hours too. I also have a 4S. Never had it happen before!