America the Beautiful pass does not get you 50% off. A Senior Pass or Access Pass (disability pass) will get you 50% off.
The America the Beautiful pass gets you free entrance to any Fed NP or Monument. This does not include special fees for cave tours, boat rides, etc.
The Senior pass is a one time fee of $80. Access Pass is free with a doctor's letter explaining that you are disabled and have a difficult time getting around. An America the Beautiful Pass is good for one calendar year. These are for the Federal passes. State passes vary by state.
