1. Take advantage of free walking tours to learn about the city in an informative way without cost.
2. Purchase combination tickets online to visit top attractions like museums and get discounts of up to 40 euros.
3. Use the 100 and 200 city buses that stop at major sights, as day tickets cost only 6.50 euros and also work on the subway.
4. Invest in a 3-day Museum Pass for 24 euros, allowing entry to 50 museums - a big savings versus individual admission prices.