Today I visited the Prague center to see all the major attractions. I rode to the center on a tram #22. There was no ticket vending machine at the station but the nearby tobacco store was selling the tickets. The tickets are based on the time duration, e.g. ticket for 30 minutes, 90 minutes, 1 day or 3 days. The ticket can be used on any mode of public transportation.
Prague is a very beautiful city. Also what is great about it is that there are so many places to eat here and the food is good and relatively cheap (especially comparing to Basel, Switzerland 🙂 ).
I was in the center early in the morning and it was raining a little. Because of that there were not too many tourists. But later in the day it got sunny and there were huge crowds of tourists everywhere.