Oyster Cards - The best deal for getting around London by transit

Although you can still use cash to get around on the transit system in London, an Oyster Card is really the best deal. There is a nominal charge to purchase a card and you can "Top Up" your account with cash. When you use the card on the transit system, the charge is automatically deducted from your account. The good deal is that they discount the fares for card users. What would normally be a 4 pound tube ride is only 1.6 pounds on the oyster card. Buses which normally cost 2 pounds per trip are 1 pound on the card. Another feature is that when the fares reach a certain amount during the day, you aren't charged any more because the Oyster card then becomes a day-pass. That amount varies depending upon where, when, and how you have traveled, but is less than buying a day-pass up front. This way you don't need to figure out your travels ahead of time to determine if a day-pass would be more economical.

What I have done is run the balance of my account low toward the end of my trip and add cash as I need to during my last day (there are machines at every tube station) and try to end that last day with a zero balance. So far I have been successful. If you don't want to do that figuring, don't worry: the money left on your account does not expire and you can us it the next time you are in London.