Apologies for sounding daft but we haven't been to London for years. We are taking DS8 to London for the first time over Easter and plan to do the touristy things in Zone 1. If I preorder an oystercard online the fee is £5 before topping it up. If we get one at the Tube station in London would we still have to pay the £5? Its not much of a saving having an oystercard for a single weekend use if we have to shell out a tenner for it IYSWIM. Thanks for any advice.