burger bars are rubbish at festivals. you need to try something better, and different.

at the lat festival i went to they had a toasty van, selling simple cheese toasty and then posh ones with parma ham and olives and stuff, they had a massive queue and the sarnies were about £4 each. There was a noodle stand, a crepes stand, a carribean stall, a cornish pasty van, and a veggie stand that sold chilli and curry and stuff.

i didn't see anyone gettign a burger. get a clue and try something different, you'll make more money than if you sell greasy burgers