Are they really cheaper?
Yes! an Oyster card is always cheaper than the equivalent fare paid by cash.
Lets look at an example, you go to London on a Saturday and want to visit a few of the attractions. You're not sure how many times you will use the tube so you decide to get a Zone 1 Travelcard. Purchasing a Travelcard would cost you £12.00 for the day and give you unlimited rides on London's transport network. The much cheaper alternative is to purchase an Oyster card and pay £6.40 for unlimited travel on the day. Even with a one off £3.00 Oyster activation fee it still works out much cheaper.
What is Oyster Daily Cap?
The Oyster daily cap refers to the maximum you will ever pay for that day's travel.
Your journey is always changed the single fare rate, up to the daily cap limit. Normally this is on your third journey meaning it won't cost you any extra no matter how many more journeys you make that day. This has the added benefit of you not having to guess how many times you'll use the tube that day and gambling on buying two single fares. It always works out what was best for you
What is Anytime?
Anytime allows you to use the ticket during peak hours (Monday - Friday, before 9:30am).
Can anyone buy an Oyster Card?
Yes! Absolutely anyone can buy an Oyster card you don't have to be a resident and you don't have to be a UK citizen. If you are vising London you can buy a Visitor's Oyster card which has a £3.00 activation fee rather than the standard £5.00 . The only difference is that you cannot top it up online and a visitor Oyster card allows you to get a refund on the balance when you leave.
Do I get charged extra if I change trains?
No, your a journey is counted as one from the time you swipe into a station and the time you swipe out. Changing trains or lines does not count as leaving the station.