101 Muni fees
This is probably one of the more confusing transportations out there.
So let's Keep it simple there's 3 main trains:
-Muni bus:$2 per adult and $.75 for Seniors & Youth (5-17)
-Muni Trains: Exactly the same, but this ride is on old school rail tracks.
-Cable Cars: $6 per single ride for children and Adult.
I recommend you if your sightseeing the city for a day getting a 1-Day Passport, its only $14 and you can use it on all muni vehicles.
Remember to save your transfer since its valid for the next 90 minutes of purchase, just in case you wanted to take another ride.