A walking tour of London will provide you with multiple free sights. You can stroll through historic London and see the Houses of Parliament and Big Ben on your way to the nearby London Bridge and Tower of London. Enjoy the architecture and the River Thames at no charge.
You can enter many of London's major museums without charge as of 2010. The British Museum, a must-see London sight, has an optional suggested donation, but no admission fee. Other free museums include the Science Museum, the Tate Gallery and the Victoria and Albert Museum.
While in London, relax in one the many vast, green parks, such as Hampstead Heath, Hyde Park and Kew Garden. Riding the Tube also allows you to experience London without spending much money, and you can watch the Changing of the Guard at Buckingham Palace and visit St. Paul's Cathedral for a reasonable price.