How does getting an iPhone on T-Mobile work?

Well I'm planning to buy an iPhone after a few months of when I have a job and since I'm on T-Mobile (no way of changing carriers), I was wondering how the iPhone on T-Mobile works. I already know its possible but I'm not sure. My question is can I jailbreak it and use T-Mobile that way somehow? Or do I have to buy the unlocked iPhone which has a simcard slot but costs $850.00 for the 64GB version (which is $450.00 more than the normal iPhone). Or do I have to do both?

You can't get one their

Get the unlocked version of the phone and go to your local t mobile store and ask them to hook you up

You can't get one on T-Mobile. Just switch carriers, T-Mobile sucks anyway. The only point they boast about is all of their "4G" but it's not true 4G… It's 3G+ and they are calling it 4G. So stupid.

I'm also using an iPhone with T-Mobile network. It works fine and great. You can definitely go on. I bought a network locked iPhone for affordable cost and unlocked it through remote unlocking method. This method of unlocking was safe, simple and very much affordable. You too can go on unlocking with this method. I got the remote unlocking for my iPhone from Wickedunlock.com. This was very helpful for me.