By Train from Glasgow (United Kingdom) to Perth (United Kingdom)

Book Early and Save: No

ScotRail does not place discounted Advance tickets on sale for train journeys from Glasgow to Perth, so you wil pay the same price per departure whether you book ahead online, or purchase tickets at the station just prior to boarding.

Though you can save money by travelling at less busy times when Off-Peak tickets will be available, so on this route you can save money by not departing from Glasgow between 16:20 and 18:20 when Mondays to Fridays are working days.
Because if you do depart Glasgow at those times only the more expensive type of Anytime tickets will be available

ScotRail offers ticketing deals when Adults travel with children or in groups
Though there's no need to book ahead online to obtain these discounts - you will be charged the same prices when booking these ticket at the station just before boarding .
If you will be booking these deals at the station it can be less confusing to book in person at a ticket counter, rather than using a ticket machine.