Do festivals pay for bars or do bars pay for a stall at festivals?

I was talking to a friend today about working as bar staff at some festivals. I was always under the impression that the festival pays for the bar to be present, however my friend said he was quite sure it worked the other way round.

Both ways kind of make sense - at festivals you sometimes have stall selling items and these stalls have to pay to be there, because ultimately they know that what they pay for a stall they re easily going to get more back than what they paid, and the festival themselves is in a position that it doesn t actually need stalls to be there so actually has no requirement to encourage them to be there (all they need is artists on stage and a bar).

However with a bar it s works both ways - the bar itself needs a stall to make money from it s wares, and the festival needs a bar (or else it ends up with a lot of unhappy people! - I was at a bonfire one year without a bar and it was surprising the amount of people who complained to the organisers about the lack of the bar so from the organisers point of view it certainly is necessary). So do the festival pay for the bar or do the bar pay the festival for the stall?