Hi Cos,
While I have never camped there myself, I believe the facilities are shall we say 'basic'. I know some of the other ten-tenthers camped there last year for the BTCC meeting which was a bit of a washout. So, I would recommend you take plenty of dry clothes etc. As for cost, try calling Brands Hatch direct or go to the website which I think is
www.octagon.co.uk or try
www.brandshatch.co.uk If you drive out of the circuit there are a few local shops in West Kingsdown including a fish & chip shop and a Chinese take-away. Of if you want to venture further afield, Dartford is not too far away. Food at Brands tends to be a little on the expensive side and to be honest, not pretty good quality wise. The Kentagon or Hailwoods within the circuit do a good breakfast including coffee for £5 (last years prices)
Hope to see you there during the year!
Stephen.