Although it has been worth every penny, the decent amount of money that you have to spend in London is inevitable. This is due to British currency (Pound Sterling) being of greater value than the US dollar, combined with the overall high cost of living in London in terms of Pound Sterling. That being said, there are great things to do in London without having to spend more money than you have to.
The hands-down, best free things to do in London are the museums. London is filled with rich history and artistic influence and you can access it all for free in the museums. If you would like and were very pleased by the experience, you can donate to the museum upon entrance, but it is not required. I have personally been to the Imperial War Museum, Tate Modern Art Museum, British Museum, British Library, Natural History Museum, Science Museum, and the Victoria and Albert Museum. My personal favorite museum was the Imperial War Museum, which had exhibits from the likes of World War I, World War II and the Holocaust, and modern conflicts. I went back to the Imperial War Museum twice and wish it could have been three times, because there is so much to see. The British Museum has artifacts from the likes of Ancient Greece, Rome, Egypt, and more. It also is home to the famous Rosetta Stone. The British Library is not technically a museum obviously, but it has an incredible exhibit of historical documents, religious texts, literature, and music. The crown jewel of the exhibit is one of the four remaining original copies of the Magna Carta. The Tate Modern has thought-provoking modern works as well as a great view of the city from a viewing terrace. Even all of the museums that I did see, there is a number that I regretfully have to leave London without seeing.
While I have not explored as many parks as I would have liked to, the two in particular that I have spent time in were great. Hyde Park is the largest park in London, situated in the center of the city, similar to Central Park in New York City. Another great park that is a little more out of the way is Regents Park. Regents Park has a large hill, called Primrose Hill, that offers a wonderful view of London and is well-worth the trip.
Yes, I know that markets are in-essence not free – you go to markets to purchase food, clothing, or souvenirs. However, you can pay for as little or as much as you would like, and they are fun to just walk through and explore even if you do not buy anything. Additionally, food stands will often have free samples sitting out, so you may get the opportunity to try a wide variety of foods for free. I personally visited Camden Market, Borough Market, Old Spitalfields Market, Brick Lane Market, and Covent Garden Market. My personal favorite was Camden Market, since it has so much and is also situated on a canal.
There is so much to see in London, and although you have to pay to really go inside a lot of iconic buildings, but a lot of things in London are incredible to see from the outside as well. You can walk around Parliament and Westminster Abbey and inspect the breathtaking architecture. You can go to Abbey Road to see the location of the icon album cover of The Beatles as well as their recording studio, Abbey Road Studios. I enjoyed walking along the river where a lot of London’s icons are. It is worth walking across the Tower Bridge, walking around the Tower of London (although I toured the Tower and it was incredible, it is marvelous from the outside as well), take a stroll through Trafalgar Square. London has so many treasures littered throughout the city that it is often worth just taking off and exploring. Since I got off of work after many attractions closed, I chose to just walk around and explore on my own fruition every once and a while. You never know what you will stumble upon.