Trying to buy a song from amazon mp3 store on my Galaxy S Vibrant Android phone, and if I am not connected to wi-fi I get this message:
You are currently roaming outside of VStream’s data network. Music downloads must be completed over Wi-Fi or Vstream’s highspeed data network.
Long story short, your sim card is very old. Go to the Tmobile store and have them set you up with a new sim card for your phone (free).
The Rest of the Story:
For many months I was having this issue and other “roaming” message problems on my phone. After contacting both Tmobile support and going into the store they were clueless about what was wrong and how to fix it. So I then gave up on fixing it, until it occured to me the other day how long I have been with Tmobile (12 years) and I thought, “I bet I am still using the old sim card from when they were called VoiceStream. Then I went down to the store and got a new sim card and now it all works fine.