Monday 20 April 2009 4.44pm
Every time I have looked at this, Oyster card works out best. You can buy them at the station or on-line and will pay a £3.00 deposit. The deposit is refundable when you return the card. You then put soem money on them as well and it will allow you to pay as you go, but you will never pay more than the maximum day rate for the zones you have travelled.
All information on how to apply for them, and cost of different types of tickets here: http://www.tfl.gov.uk/tickets/faresandtickets/2930.aspx
and on oyster cards here: https://oyster.tfl.gov.uk/oyster/entry.do