Tell me about apple os.and is the iphone 3g good?

Please tell me about apple os. And how much will it cost me to buy apple iPhone games and app software? Please tell me that y iPhone r much costlier than andriod phones. I mean y people buy iPhone instead of andriod. What this os means in the iPhone. I promise u that if you help me then I'll surely rate your ans 5 stars.

I changed from an IPhone 4 to a Samsung Galaxy SIII Mini and i have no regrets!
you get pretty much all the apps that are on Apples App Store on the Play Store (Android Store), apart from Apple Specific ones.
and its iOS not Apple OS
Some apps are free and some you have to pay for (with Apple and Android)
I suppose the advantage to Apple is that it all Syncs with Itunes, so when you buy a new IPhone, if you Sync it with Itunes, all your settings will be transferred from your previous IPhone to your new one.
Apple and Android are pretty much the same price.

its about what your happy to use and what you want to buy