Questions About Phones And Cell Providers.

So, my girlfriend's phone went for a swim lastnight and is done for. She wanted me to see about picking her out a new one since I'm more tech savv than she is. But there are still a few things I don' know, nor am I 100% sure I know what I'm talking about. So before I brought anything to her I figured I'd cover my bases here. One of the phones I found on Amazon said it was T-Mobile in the item name, but under carrier compatibility is said it was fully supported by AT&T, but under the T-Mobile it said "No Voice/Text and Partial Data Connection" I can not seem to find anything on what that actually means, everything is just people saying do disregard that because it works on T-Mobile just fine.
Is there a way to make sure her SIM card is not damaged? As of lastnight, until the phone ran out of charge, the phone did turn on and she could move around a little bit, assuming becomes if water damage to the backside of the screen. Would that mean it's fine?

Can she just pull this SIM card out and insert it into the new one without going to a T-Mobile location?

 

I can no longer edit this post, I apologize for the few grammatical errors, I was trying to get that posted and not be late coming back from lunch. I also wanted to ask about unlocked phones. Is there any difference between them and regular factory phoned outside of unlocked ones can be used on any carrier?

 

SIM cards are sealed, so it wouldn't get waterlogged. Operating the wet phone won't help it, though. Pop it in another phone and see if it works.

You may need to set the APN manually to get data service.

You will need to make sure it works on your provider's particular cellular frequencies.

 

Why don't you just buy a smart phone that is both SIM-Free and unlocked to any network

 

Thanks for the input guys, I'll have her look into it.
(Sorry for the delay, works been crazy)