I flew there last summer. I can't remember the cost (although I can look it up if you like), but I don't think it was either very cheap or very expensive. I went there with a large group of aeroplanes (25ish) and perhaps for this reason we were parked quite a way from the terminal. When you come to pay you will probably have to visit two places, the airport payment office and the briefing room where there was a small amount to pay for navigation charges, about £10 IIRC.
The real pain is getting back airside. I had to do it a couple of times, and on one occasion it took me over an hour. Don't be tempted to stay in the hotel opposite the terminal unless teh only other option is a park bench, and only then if the park bench is broken.
PM or email if you would like more info
Ian
PS I flew in VFR, but I was still given vectors to the ILS