Do i have to buy internet if i have a 3g sim card?

im on 02 pay as you go n luking 2 buy htc 7 mozart 3g phone... i was told dat i need 2 take a internet package dat cost �6 per month if i wnted 2 buy this phone coz itz a internet based phone all i want 2 knw is dat if i get a 3g sim card do i still have 2 take this internet package... plzz sum1 help me