Thanks for a quick response guys.
Was a hidden cost I wasnt expecting. Just got XBox live and all the gizmos for my younger brother for his b'day. My other younger brother ofc wants his gamertag online and I was planning on getting myself one. But with this being the case they can share one and i'll stick to going online with the PS3.
Is this likely to change at anypoint in the near future, as it does seem an extortionate cost for a large family with their own gamertags.
Anyway, thanks again for the quick response.