''Are you stark staring mad?" That was the response from Morag Deyes, the artistic director of Dance Base, Edinburgh, when she heard I was bringing a show to this year's Fringe Festival. Morag is never anything but blunt, but her comment did make me stop and think. This will be my fourth Fringe show in 12 years, and they have all been financially crippling. So why am I venturing once more into the perilous waters of self-production in Edinburgh?

The time to do the Fringe is when you are young; when you enjoy sleeping on the floor in a crummy flat, parading extracts from your show up and down the high street and giving out endless leaflets that go straight in the bin. Only when you're young are you sufficiently insouciant to do mad things to get your-self noticed - like the student who made the headlines when she hired a bare room for her show and had her boyfriend provide the lighting by shining a torch in her face.

For performers, paying to put yourself on stage is the worst possible scenario. No self-respecting professional would normally dream of performing without a fee. But every August, thousands dig their hands in their pockets to present their work, possibly for a daily audience of two old ladies and a dog. Apart from all the costs of mounting a new pro- duction, the big pay-outs are for accommodation, publicity and venue hire. And some venues turn out to be less than ideal in more than monetary terms. Try delivering a serious monologue when the strains of an Irish jig can be heard drifting up from the venue downstairs. Or performing in a courtyard where the chemical toilets close by give out such a stench that you need a peg on your nose to get through it.

Still, that isn't as bad as paying through the nose, which is what you do when it comes to accommodation. Rents treble in price during the festival. This year, one agency offered me a tiny one-bedroom flat for £350 a week. It was near Valvona & Crolla - a celebrated Italian deli with hanging salami and cheeses and a cafe at the back. "Take it," my partner urged, "then we can go to that Italian place for breakfast!" Such is the lack of proportion that overcomes you where Edinburgh is concerned that I seriously thought about it for a while, until I came to my senses.

The awful thing is that the agency in question was no different from any other. The problem is not so much the odd Rachman; it is that everyone becomes a Rachman during the festival, when greed is regarded as a virtue. Edinburgh residents know they can up sticks for three weeks in August and make a killing, so that is what they do. If ever there was a spirit of generosity and helpfulness around the Fringe, it has been overtaken by rampant commercialism - the desire to milk tourists and performers of their every last penny. Indeed, if anyone offers performers a cut-price deal, there's a bit of a hoo-ha. This year, a new venue is settling for less than the customary 40 per cent of box-office takings, and apparently there have been murmurings of disapproval from some of the other venues.

In Edinburgh, none of the normal rules applies, and most performers find themselves paying not just for their space, but for all kinds of add-ons. Where else would you have to pay for the printing of tickets? Probably the most bizarre and unreasonable cost is the royalties we pay for the use of recorded music, which go through an organisation called PRS. Now, I am happy to pay musicians for using their music, but unless they are registered with PRS (and mine, being Middle Eastern, probably aren't) they won't receive a penny. What happens, then, to the money that I have no choice but to pay? It was explained to me that it is simply shared out among the organisation's registered musicians, even though I haven't used their music.

And so it goes on: £200 here, £200 there, and little by little the costs mount up until, even on a modest one-person show, you have spent three or four grand. If you have ever wondered why there is so much stand-up comedy on the Fringe, here's your answer: it's cheap. No costume and lighting designers or extra technicians to pay, no stage manager, no additional lights to hire, no rehearsal room, no royalties. You're just up there on your own with your jokes.

Not that I recall ever going to see stand-up in Edinburgh. On the other hand, I've seen wonderful theatre, dance and music - and most of it on the Fringe, rather than in the official festival programme. I have seen it in dusty, abandoned theatres, in caves, churches and bank vaults. When I see inspiring, well-produced work, it fires my imagination and re-vitalises me. And there are so many hundreds of shows to choose from that you would have to be blind, deaf and dumb not to have at least a few peak experiences.

So when people ask me why I am taking another show to the Fringe, this has to be my answer. It's always a great experience, performing in that buzzy atmosphere, when Edinburgh is at its most European, up and open and partying into the early hours. You don't have to be mad to do it - but it helps.

Wendy Buonaventura is presenting her one-woman show I Put a Spell on You at the Metro Gilded Balloon