You can buy a ticket Zurich - Rigi Kulm. You could also buy a ticket Zurich - Rigi Kulm - Luzern - Zurich for example, even with a boat as part of it. But the best option is probably a Saver. Day Pass, as that is valid on the Rigi, the Lake Steamers etc… So good for anice trip.
(and lastly: It is just “Rigi”, not “Monte Rigi”…)