So, do you think you might need a car while in London?
If you have a group of any size and plan on visiting Windsor Castle, getting a car might be your best bet - it will cost too much money for your group to travel by train from London to Windsor.
Anyway. If you are looking at a car in London, you might have to worry about congestion charges. Well, depending on where you are or what time you leave or go back to your home base, you might not need to pay congestion charge. So check these pictures out and see how you avoid paying congestion charges: