Your question is not clear - perhaps you can clarify?
In general you must have a membership in order to be able to use the 48 network at all. After that you can buy add-ons as needed - e.g. if you use up allowances bundled with your membership or for other out of bundle services (e.g. roaming etc.). You cannot use 48 without a membership and just by purchasing add-ons as far as I know if that's what you're asking?
Hope this helps.
