Can't stream away from wifi

[davednyc]

Hi - 

I have just signed up for a free 30-day trial with Spotify Premium.

I was able to stream content at home (wifi), but am unable to stream once I left my house via 3G.

I have an iPhone 4, with Verizon service.  I can see my playlists, and it looks like I should be hearing music.  I can use other streaming services fine.  I am not in offline mode.

Is this typical /  expected?

Dave