倫敦交通一問

What you can do is just do the basic which is a Oyster Card... Oyster Card will have a capping rate which is basically GBP0.5 cheaper than buying a 1Day Travel Card... So for example, Zone1+2 Day Travel Card is sold at GBP5.2 while for Oyster Card, it will be GBP4.7 of maximum reduction (if you stay in Zone1+2)...
Otherwise, you can consider getting a 7Days Travel Card... Which will be slightly cheaper than using capping rate for 5days or more... The 7Days Travel Card will be inserted in the Oyster Card which means they will not reduct anything from your card during the period (unless you are travelling out of the Zones)...
Oyster Card is basically a Octopus Card which will cost GBP13 (GBP10 as credit, GBP3 as deposite)... The credit will be deducted each time you travel (that require to pay)... And the GBP3 deposite is refundable at the end of your stay...
I would personally suggest you to use a 7Days Travel card, as it will be cheaper than the capping rate already as long as you use it for 5days... Also, they will allow you unlimited travel all day long which the capping rate will be higher if you travel before 9:30am (before 9:30 is peak hours while after 9:30 is off peak...)
Here is the information for 1day travel card: http://www.tfl.gov.uk/tickets/faresandtickets/oneand3daytickets/2911.aspx
While for 1week travel card: http://www.tfl.gov.uk/tickets/faresandtickets/seasontickets/2912.aspx
If you have anymore questions... Dont be hesitated to contact me or ask further detail here...

唔好意思 想問問交通平均費係幾多度?