What's the difference between an iPhone 4 and iPhone 5?

Basically, this is my first time getting a smartphone (I'm a teen) and I basically had to sit down and have a long talk with my parents, practically begging them to get me one.
Eventually we agreed on a family plan for the iPhone 4 which comes to about 100-200 dollars a month. That is expensive for us, the phone itself isn't but the monthly plan is.
If I get the iPhone 4 will it be entirely different than the iPhone 5? I've seen the phones side by side, but not the features-- is it alot better?

Added (1). Oh and I'm mainly going to be using this phone for texting & apps.

Well alot of the features are the same, but a few differences are:

iOS 6, larger screen, improved Siri, flyover on the maps application, passbook, higher resolution camera, and a new charger.

Personally, I would get the 5.

The iphone 5 is much better because you have a bigger screen also the data internet connection is much faster. The iphone 5 can connect to 4G LTE data internet speed. The iphone 4 only connects to 3G data internet. The price starts at 199.99 for the iphone 5.It depends on how much you can afford with the purchase either iphone 4 or iphone 5 cell phone.