I done one at Elvington and cost me £550. Got shown the track (airfield with cones) n an RRS then got thrown straight into an Atom, then a DB9 (which was boring after the Atom), Ferrari 360 CS (best instructor), Audi R8 and then a Lambo Murci LP640. Took all day and had time slots for each car and you also then have the option on the day to pay a £30 insurance waiver incase you total one of the cars, also Got a pic of me on track in each car (about £8 each) so just be aware there is more costs on the day. But really enjoyed it and want to do another one but on an actual track. Also on my one there was 2 companies operating on site and you could book extra laps and other cars on the day at reduced rates. I got 4 laps in each (out lap, 2 hot laps and in lap). But mine was back in 2008. Also done a 2hour one on one driving a 40' arctic.
Next one I'm looking at is the american muscle car one at goodwood with the Viper (favourite car), Vette and 'Stang.
Here's the site I booked on, they used to do only experience and track days for cars but do everything now. You can chose by car type, location etc.
http://www.trackdays.co.uk/Once you've found the one you want check the actual site for the track or try and find the actual company providing the experience direct as it could be cheaper or you could book an actual date rather than getting a voucher.
Hope this helps