Replying to I need a new cell phone please help me

Ok so I was drunk and lost my phone like 3 months ago.  Anyway I need a new phone.  So if I get an "unlocked" phone does that mean I can use it with any carrier?  Right now I have T-Mobile but I want a Nokia phone so it has to be unlocked.  I have $300 for a phone and I wanna get a dank Nokia one like the Nokia N91 or N81.  So are there better phones for $300 or are these pretty legit?  I've always thought Nokia's high end phones had the best features/looks.  So I'm just not sure if an "unlocked" Nokia will work with T-Mobile.  Help please