Can you use any Tmobile data plan on a factory unlocked iphone 4/4s?

I wanna buy a iPhone but since my parents wanna stick to tmobile so i'm forced into unlocking an iPhone if i buy one. I don't wanna spend the 30 bucks/month for 4g cause between me, my brother, and my mom, its pretty expensive. So i was thinking about getting the 256 MB plan for $10/month. NOTE that i'm not really gonna be using my data cause i usually don't go anywhere that doesn't have Wi-Fi. So really, my point of confusion is if i'm able to use that 256 MB plan on an iPhone thats factory unlocked.

8GB iPhone 5 or 16GB iPhone 4s?

I'm getting an iPhone soon and I only want to pay $199. Which is the best option? I have heard some bad things about the iPhone 5, but I could get more space on the 4s.

Added (1). I meant a 16GB iPhone 5 and a 32GB iPhone 4s haha

Iphone 4 stolen: is there any way to track it for free?

We had a new iphone 4 for 4 days. We didn't have time to learn about activating any sort of gps on it. It was stolen today. I know that there has to be someway we can track it down but all the research I find say you had to activate an app first. That being said there still has to be a way but I can't seem to sift through all the bs on the internet to find it. Please let me know if there's an inexpensive, if not free, way to do this. Please post it in an unambiguous set of instructions because as I said before I can't seem to sift through the bs. Additional Details: All we have is my laptop that runs Windows 7 and Unix. NOTE: All the things I have found to locate it have been apps which makes no sense! If your iphone is stolen how are you going to download an app to find it?

Is iphone 5 on Cricket unlocked?

I've seen some news talking about cricket has an iphone 5 that is only 499 dollars and I'm just wondering does it function like other contract iphones? And is it unlocked?

Iphone 5 screen protector on ipod touch 5th generation?

Everyone is selling iphone 5 screen protectors but none for the ipod touch 5.so since they both are 4" displays. Will it work in theory if i put the iphone 5 screen protector on the ipod touch 5? I don't mind the front camera getting blocked.