One of the first thing that definitely comes to my mind would be WHY ARE LONDON TRANSPORTATION SO EXPENSIVE!!! Really, you would simply feels the hole in your pocket getting larger and larger each and every time you tap the oyster card. Especially for Singaporeans, since the pound is double the price of the Singapore dollar. For those who are unsure, the oyster card system is a combined transportation ticketing system for use in London, with an oyster card you can travel on ferries, bus, DLR, OverGround and the well known Tube. It can be loaded with credits at many places, including newsstands and convenience stores. Although not as comprehensive as the Hong Kong octopus card, it is kind of alike to the ezlink system we have in Singapore, perhaps only double the price. My heart really hurts man, throughout my 5 days stay in London, I spend close to 40 Singapore dollars on the tube alone! Oh god, that is like a Burger & Lobster meal man! Every ride on the tube within the same zone is around 2.30 Pounds, even one station would be the same price, with a daily limit of 6 pounds. Being a tourists the min rides that you will usually take is about 2 per day, so that is already close to 10 SGD. I would say to budget this for your stay in London. One advantages of the oyster card that I really like that it is practically free, just buy a card and load it up, you can refund all the credits inside at any tube station. I mean like it is really a official matter, they will refund all of it, down to the cents and you have to sign on the receipt. This is better than the Singapore ezlink, where you have to pay 5 dollars for the card.