The socket...

The "free Net" is actually always on. The iDEN network uses digital data packets to communicate with the phone for some text messages ("Net alerts") and its voice mail notification.
Using the hack shown >> HERE << you are piggybacking on to the connection. It is the same connection you use with the phones built in WAP browser that usually just shows carrier specific bookmarks.

However, for 35 cents a day Boost will open another connection that will allow JAVA apps access to the net. This a completely different connection and actually works independent of the Bluetooth connection.

That is, I can browse where I want with the tablet AND open a JAVA instance of Opera's browser and browse to a completely different site independently.

Without the 35 cents a day the Opera app will not connect. The tablet via BT will still work though.