When using Ticket Tailor, you can set up a booking fee, for example, if you want to pass on your fees.
Booking fees are set per ticket, so you could have some tickets with a booking fee and some without.
If you have a ticket or product with a booking fee of zero, this is showing because at least one other ticket or product in your event has a booking fee with a value.
For example, your event might have:
1 x in-person ticket for £10.00 and £1.50 booking fee
1 x free online ticket with no booking fee. This will show with a £0.00 booking fee on your checkout page.