Default [Q] Never managed to access the Internet

Hi I have had my Samsung GT-S5830i for a few months now but have never managed to access the internet other then through Wi-Fi at home. Furthermore I have never been able to connect to any free Wi-Fi away from home say in a pub. Is there something in settings that is preventing this?
I am with Giff Gaff that uses the 02 network.
Any help would be appreciated.