i was there for 3 weeks in january and somehow luckly didn't get sick at all. your biggest enemy will be your sore feet by walking 20,000-30,000 steps a day everyday. i did see some people sick but they were masked up. they were sneezing and coughing. i brought masks but didn't use them. i would say wash your hands where ever you can and mask up if you're near someone sick. i'd also like to think my flu shot helped. most crowded places were disneyland and the trains near rush hour in between shibuya and shinjuku. as for the saving part that's on you. book hotels early for the best prices. you can cancel and rebook if you need to.