Clean, spacious & smooth the metro will take you around the stunningly beautiful city of Budapest with ease. A single journey ticket purchased in advance will cost as little as 97p on your Revoult card, HOWEVER....... as so many others have said, you have to use it correctly. There are ticket inspectors praying on the unsavy & they are extremely aggressive. You have to validate your ticket at an orange stamp machine. They are not easy to see either. We were lucky we made such a fuss and didn't flinch when they threatened the Police, lots of arguing. They were not interested in anyone else while they had us, to appease & shut me up. One of the inspectors attempted to stop someone else who ignored them and ran up the escalator without chasing ! That was it for us. We pushed past them and followed the other chap up ! We got lucky, but they are clearly there to extract 25 English big ones off you per person.
Thankfully, other than making us feel like Budapests most wanted for the day, it hasn't changed our perspective of the most beautiful European city I've been to !