Oyster Card

The cheapest way for you to move within and around London is to use
an Oyster Card. The Oyster Card can be used to pay as you go and can
store up to 90 pounds of credit.

The Oyster Card can be used on bus, Tube, trams, DLR, London overground and some Rail services.

Visit the following link to find out more about how and where to get your Oyster Card:

http://www.visitlondon.com/travel/oyster/