If i buy unlocked iphone 5 and insert my t-mobile sim card in it, will it work?

T-mobile offers no iphone and i have 2 year contract with them. I read on internet that many t-mobile users have started using iphone after they buy it unlocked.

But i went to at and t store and they said it will not work with t-mobile and that if i sign up contract with them, only then it will work.

so who is liar - the internet users or the at and t shop?

There are ways to get it working. Check xda-developers.com

Yes, if you buy the GSM unlocked iPhone, it will work with your T-Mobile SIM card, given that you have cutten it down to the nano SIM size so that it will fit into the SIM tray in the iPhone 5. If you don't know what I'm talking about, Google how to cut your SIM card down to a nano SIM size.

I just bought an unlocked iPhone 4S from the Apple Store and got a micro sim card from T-Mobile for free from the rep at the store, popped it in, used the activiation kit code given to me at the T-Mobile store and voila, using an iPhone on T-Mobile. Once your up and running on T-Mobile, you may have to tweak your cellular data settings in order to get your picture messaging and texting working like normal, but that's minor and you can google the instructions on how to do that easily. Be careful, the speed in some areas with T-Mobile is like 2G, T-Mobile is currently working on upgrading their towers, I've heard that some people have been using Straight Talk as well to get the $45.00/month unlimited text, talk and data (data: up to 2GB works at 4G speed then anything after 2GB starts to slow down the internet, but it's still unlimited).

T-mobile is lying. Assuming the device is unlocked it will work with a tmobile sim.

if you need to unlock an at&t iphone go h ere: http://gsmunlocklabs.com/unlock-iphone/