Interesting blog post on this here:
http://www.matthewlewisdisplays.co.u...orth-the-cost/
But basically "...my stand which will be in hall 3 cost £375 per square meter, I have a stand which is 6m x 1m and comprises of a shell scheme and carpet. If I want lighting that will cost £90 per strip light, electrical socket with hook up will cost £80 per single socket."
Maybe walking around as a visitor with an ad on a tshirt might be cheaper. Until you get thrown out that is!