Some passengers were able to travel on buses for a £1 due to a ticket machine error.
A number of First buses operating in the city experienced a problem with ticket machines not working on Wednesday and Thursday.
While the machines were not working drivers used emergency tickets, charging all passengers £1.
A spokesperson from First said: "We experienced a problem with our ticket machines on Wednesday and Thursday, which affected a number of the buses in the West of England.
"The problem was related to an error in the back office system which caused the ticket machines to crash unexpectedly.
"While the ticket machines were not working the drivers were using emergency tickets and charging customers a flat fare of £1.
"The problems have now been fixed and all the ticket machines should now be working normally.
"We would like to apologise to any customers affected by this issue."
