Pricing
The pricing system is fairly complex, and changes from time to time. The most up to date fares can be found on Transport for London's FareFinder website (see External links).
To encourage passengers to switch to Oyster, cash fares are generally much more expensive than PAYG fares (including Bus and Tram fares):
A cash bus or tram fare is £2.30, while the single Oyster fare is £1.35, but capped at £4.20 for any number of trips in a day. Using pay as you go, a single trip on the Tube within Zone 1 costs £2.00 (compared to £4.30 cash), or from £1.40 (£4.30 cash) within any other single zone.
Read more about this topic: Oyster Card