You can use TFL's single fare finder to figure this out by inputting your start and end stations. For the purposes of giving an accurate answer for Quora, though, I made up a journey using two example stations in Zone 5: South Ruislip (west) to Buckhurst Hill (east). There are two options:These stations are both on the Central Line, so you can ride the underground train directly through the middle of London via Zone 1. With Oyster, this single journey will cost you u00a34.70 at peak time (Monday-Friday between 06:30 and 09:30 and between 16:00 and 19:00) or u00a33.10 off-peak (at all other times). As a cash fare, this will cost you u00a35.90 at any time.Alternatively, you can avoid Zone 1 altogether: Central line from South Ruislip to Shepherd's Bush, then walk over the road and get the overground from Shepherd's Bush to Willesden Junction, then change at Willesden Junction to get on a train to Stratford, then get back on the Central line at Stratford and ride it all the way out to Buckhurst Hill. With Oyster, this journey would cost you u00a32.80 at peak time and u00a31.50 at all other times. There appears to be no cash fare available for this journey - this is probably because to receive the lower Oyster fare, you are required to use the pink-coloured Oyster readers at Stratford station to declare that you haven't been through Zone 1. The cash fare would likely be the same u00a35.90 as mentioned above.The TFL planner does say that some journeys will be charged as if you've gone through Zone 1 regardless of the route taken, so for an accurate costing you'd need to input your actual start and finish stations at the link above.