Budapest Card

Cover all the essential must-sees and save a load of money with the Budapest Card. See the best of the Hungarian capital with a 24-hour, 48-hour, 72-hour, 96-hour or 120-hour pass. See all the museums, plus get two free walking tours (one in Buda, one in Pest), free public transport, free entry into the Lukács Thermal Bath and Pool, and loads of dining discounts to boot. If you're Hungary for adventure, this card will make it happen!
The Budapest Card gets you access to all the city's major attractions, plus restaurants and more. Opt for the 24-, 48- or 72-hour option to tailor your card to the length of your stay.
The varied discounts include one-time entry to the Budapest History Museum, the Hungarian National Gallery, the Hungarian National Museum, and more Budapest mainstays. You'll also get to see Buda and Pest with your two free walking tours; gain a deeper appreciation of the city on the Danube, and its monuments and bridges.
And take advantage of free public transport and free entry to Lukács Thermal Bath and Pool (you weren't planning on coming to the Spa Capital of Europe and not hitting a thermal bath, were you?)
With all this, plus discounts on restaurants, attractions, churches, and baths, this is by far the cheapest and easiest way to make the most of your trip to the 'Pearl of the Danube'.