i'm sure i could get this by googling but it's more fun to ask YOU PEOPLE. how do they work in relation to bandwidth usage on online services?

this Spotify app that's been announced is making me seriously tempted to get one but i have no idea about these things at all. i've never had a contract phone or a phone with internet.

does this app also excite anyone else? every day i find more stuff on there i want to listen to, and i totally don't have the time right now as i can't use it at work. <3 spotify.