Hello Spen
Welcome to the SBB Community. We are a customer support forum run by volunteers.
No, the purchase at the counter is free of charge. The counter staff does not sell saver tickets which are only available online. Other than these, all products that are available online can also be purchased at the counter.
Train staff does not sell tickets. When you enter a train, tram or bus (with a few exceptions), you must be in possession of a valid ticket.
Kind regards,
Roland