Located around 2 kilometers away, Budget is the closest car rental outlet to Trafalgar Square. Europcar and Avis are other options. Whether you’re planning ahead or on the lookout for a last-minute bargain, Expedia can help you find the right set of wheels for your trip to London. Make sure to click on the “Great Deal” filter, which will display the lowest-priced vehicles for each category. You have a choice of multiple car rental companies close to Trafalgar Square.