So one for Mason:
In the UK. Well England at least but I've not heard of it being different elsewhere, when you get on a bus you say where you're going, "town centre", and the bus driver tells you the price, and you pay and it spits out a ticket and you go n sit down and get off at your stop. The price is based on the distance/stops between where you got on and where you get off. For example this journey is £1.45.
Ticket machine looks like this:
You can buy day, weekly and monthly passes, or be a student(secondary and further, not aware of it for HE), or OAP and you just flash the pass/ticket at the driver and doesn't matter much on where you're going.
Here's an OAP with their swipe card, it's RFID or something:
(I should maybe note I've never actually seen one with a passenger side screen though)