i dont have a betta but i'd personally invest in a small filter and DEF. cycle the tank before you go out and buy any type of fish. if you dont know what cycling a tank is =
and type in.... fishless tank cycle
or read some threads on here about cycling a tank.
other then that you're going to need betta food and you should be just fine. if you want to get really fancy you can upgrade to a 5 gallon tank, get a small light, small heater, thermometer and whatever tank decorations you choose however your 1 gallon should be just fine for a college dorm room, especially since i know how they get ( with traffic )
JUST REMEMBER TO CYCLE THE TANK FIRST!