Hi Paul, welcome to Mobile D.J Chat

. Firstly prices for Disco's vary just like everything else, Property, Taxi fares, even the good old pint

. A lot depends on your actual area, although from talking to other D.J's there does seem to be the old "North / South" Divide. Mainly the price that D.J's charge appears to be more expensive in the South, than say in Scotland or the North East.
Don't quote me on this

- But I do have colleagues in the Essex Area who charge £250 a night, then again I know of D.J's in the Lake District who charge only £80 a night. I believe that you could also expect to pay around £300+ a night for an Established D.J in London - Maybe even more.
Other factors to take into account are your local area. Are you close to a large town or City Centre?, since demand (and prices) in a larger populated area for D.J's on a Friday or Saturday is likely to be higher in an Urban area than in a rural area. Then again if you are the only D.J for 30 Miles then you could possibly charge £££'s for those young farmers Gigs!.
Of course, whatever you decide to charge also depends on your ability as a D.J, the type of show that you are offering and whether you also offer Karaoke or not?. Other things to factor in, are the type of function that you have to do, how long it will take you to travel there, How long it will take you to set up and pack away (i.e do you have to lug your gear up 3 flights of stairs!!). The length of the function, and if you are in the middle of a city centre - your car / van parking fees
A good way to find out what is being charged locally is to enquire as a potential customer to one of your established competitors!!! (This is done in any business so don't feel too guilty!

). Call a few of them asking for a price on a wedding, 21st etc for say 8pm - 12. take all of the prices and find the average price.
I advise all people starting up from scratch to charge slightly below that charged by your lowest priced competitor. But don't undersell yourself either since your customer will be suspicious if you are £50 below everybody else!!!. Fix a fair price for your area, and offer a fair and reliable service and your bookings should roll in.
It is always a good idea to offer potential "Regular" customers - such as your local Pub, Hotel, Function room etc a good discount on frequent work or block bookings - as much as 25% lower than your standard price if the work is weekly or if they are loyal and pass business to your roadshow only. Pub work - i.e 7 - 11 is always the more competitive area of D.J'ing and you may have to go in with a very low quote to compete. Although an advantage of this work is that it's open to the public (getting more bookings from punters for Weddings etc) and often booked during the week - which still frees up your Friday / Saturdays for your more lucrative Function room bookings!. Decide if taking Pub work locally is worth it - but don't run it at a loss!.
If you choose agency work then the agent usually sets the price then pays you - less his 10 - 25% commission. If you do choose agency work then ask around first for a reputable one!. Many are set up as fly by night operations which get the D.J to do all of the work then disappear with all of the fee

. I stopped taking this work because of too many cowboys, but decide for yourself and ALWAYS make sure you get a written contract even if it's only for one booking!!.
Some good tips on finding regular contract work are by approaching:- Football / Cricket Clubs, Council Run Town / Village Halls, Leisure Centres, Hotels with function suites, Conference Centres, Universities, Organisations (Drama Groups, Young Farmers, Student Union, Working Mens clubs etc). Remember to offer these a discount on regular bookings since many hotels etc will charge a fee for the hire of the room plus a fee for the disco and if you offer a discount to them then they are likely to maximise THEIR profit just for booking YOU.
So the easiest way to find out prices is to contact a few local competitors (Yellow pages is useful

) .
If you need any more advice then please post your questions. Good Luck with your venture.
BTW: £300 would be around average for my area on New Years Eve (Cheshire Area). A lot would also depend on how late the booking is made

, I often get calls on 30th December for People who have left booking a D.J too late or have been let down by other D.J's and are in a panic, you could be justified in charging over the odds for this service, but it is personal choice!. maybe other D.J's could post their policy and charges for New Years Eve?.
Chris