If you are looking for a direct travel from point A to B, in your case Zurich airport to Andermatt. You can save money by booking in advance with so called super saver tickets, you will have to take the specific trains you booked. (Like @RolandP said, be careful when you look at the price, the super saver fare start with a % is by default displayed assuming you are with a half fare card) From what I checked just now, a random Thursday (16th) in mid march the super saver ticket rate is around chf 15 to 20 (So, for you without a Half fare card, 30 to 40)
The point to point ticket will cost you 50.2 chf as roland said, you depart at anytime you want, you can even stop in the middle of your journey and hop on a later train.
I recommend Saver Day Pass if you are planning also on doing some little trip already on your arrival or depature day. You will be able to use all kinds of transportation (except things like Jungfraubahn, Titlis etc…). For example in the middle from Zurich to Andermatt here is mont Rigi, lake zurich, zug, luzern… The boats and cogwheel trains are included in the Saver Day Pass. It starts from 52 CHF but from what I saw the price for the middle of this month is already at around 70 to 80, at the end of the month it is still at 52.
Hopefully you will find the info helpful 🙂