I remember someone was asking me to help stick a night on and i emailed some places and i think people like bassline smith for instance gets about £500 a set, though the company said it would depend on the size of the club,
ie if they know you only have a small club and thus profits would be smaller then they'd charge less.
I can't remember the exact prices, as i had a list of the people on their books with prices, but i think the middle ground djs like bassline smith, hazard, twisted individual would be getting 400-500 ish range, but i'm sure andy c would higher up the ladder. But £2,000 is a lot of money just for doing a set, i think people like carl cox, oakenfold and Paul van Dyk would be getting these prices, but if you think about it they draw in the crowds and if you charge £15 a ticket and you get a big crowd it's worth it...
I guess if you are really interested you can just email one of the companies and pretend you're looking to book them for more info!