I myself was a big culprit of this – I moved into zone 2 in my final year, and the bus was no longer a speedy enough option for me to get to campus. So, facing my new Tube-shaped reality, I set about getting my Oyster card once term had already started…big mistake!
Once sending off your Oyster card application to TFL, it can take many weeks before you receive your card in the post, and you cannot use a digital version meanwhile. This card is essential for any commuter, as it gets you discounts on weekly and monthly travel passes, and when paired with a Railcard, it gets you a further 1/3 discount on off-peak travel.
The takeaway message is to get your Oyster card sorted as soon as you have your King’s confirmation. I know the card application fee (around £22) and the general admin of it all can put you off, but the future version of yourself will really appreciate it.
You can find out more information about travelcards and public transport discounts on King's Answers.