Can I use an iPhone with my T-Mobile phone service?

Someone had just given me a windows phone, but I already had T-Mobile service and apparently the two aren't compatible. So I have to buy another phone. I was thinking about maybe buying an iPhone, one of the older ones, but wanted to make sure that it would work with my T-mobile.

What is the meaning of this app is optimized for iphone 5?

I have checked some apps on the apps store and the apps say "this app is optimized for iphone 5."what does it mean? Does it mean that these apps are not gonna work in the previous versions of iphone? I'm using iphone 4 with IOS 7. Will the apps work in my device or not?

If you wear really expensive stuff and have expensive things are you rich?

I live in a place wear the current trends are:

Sperry's 64$-96$
Uggs 150$-350$
Nike tennies 100$
Toms 50$
Miss me's 100$-120$
Under Armour sweatpants 40$
Under Armour and Nike spandex 12$
Under Amour sweatshirts 56$
Under Amour Headbands 15$

So if i have more than four of each of those and the newest iphone with the best memory for 799$ and my parents have 10 cars and we have horses and 3 big fancy new trailers with tons of big expensive fancy new tack and a big house and lots of animals and tons of other expensive things like over 10 thousand dollars in jewelry and over 20 thousand dollars in each of you 3 kids bank accounts are you rich?

Why is iTunes deleting my music every time I plug in my iPhone?

I have my music in my music tab under itunes media. But, i have separate songs in my library. Whenever i add those songs from my library, it is fine. But when i decide to add my music from my tab, those other songs get deleted. Is there a way to freely edit my music without itunes constantly syncing?

How long does it take apple to fix an iphone?

I have water damage on my IPhone and I was wondering if I took it in to the closest apple store, if they would fix it right then and there or would I have to pick it up days later?

How come on Iphone there's only a keyboard?

I mean how come they don't employ that line thingy android uses? This freaking key board is so small typing is annoying because i have to keep going back to correct something when my sausage thumbs hit the wrong letter. No, auto correct makes things worse