You can pay on the buses in Budapest. Only possibility to buy bus ticket is through the driver,as there is no ticket machine inside any Budapest public transport bus.
However, you have to make sure to have Hungarian currency as exact amount for the ticket of the bus. In fact, it is better to have coins than currency notes as most of the drivers in Budapest buses do not have change. Hence,ticket may be more expansive, than what you could pay when buying a paper ticket from the driver.
Although for tourists visiting Budapest, it is recommended to buy a Budapest pass where bus rides (except 100E) are covered. However, if you on board a Budapest bus without any pass or a ticket, make sure to visit the front door of the bus to buy ticket from the bus driver and validate it right away.
Many tourists make this mistake of buying ticket from the bus drivers,but forget to validate the ticket in machines inside the bus.In such cases, you may still get fined by ticket checkers as the ticket was not validated.
Buses in Budapest come in red and blue color, and both kinds of buses you can pay for the ticket on the bus by buying ticket from drivers. There can be once exception, when a bus driver can deny you offering ticket. This happens when the bus is starting its journey and there is still time for a person to buy tickets from the ticket machine next to the bus stop.
Paying for paper ticket for 100E bus on the bus is a rare possibility,as there are ticket vending machines on all 4 bus stops of 100E. You may be able to buy Budapest 100E bus ticket from bus driver on Astoria or Kalvin ter. As 100E bus is not stopping at many bus stations,hence, better to buy ticket from ticket vending machine.
