Hello and welcome John
Dan (dukesy) has posted a comprehsive list of info regarding startup and i highly recommend you have a read through, Gathering up a bunch of kit is the easy bit.
when you are ready to get going please bear in mind this simple but worthy comment - Buy Cheap - Buy Twice
Many would be tempted to go out and pick up new budget gear which they soon realise is not up to the job or doesnt suit the long term needs. I appreciate in some cases we have no choice but i have been there and done that. Budget gear holds no secondhand value.
Typically a cheap cd mix unit (twin cd player + mixer) is an ideal starter but after a while you may feel the cd or mixer functions are lacking and you would have to scrap the lot and start again. Same with cheap l.e.d lighting effects, look great on promo videos but when you get them to a gig are dissapointing especially since smoke machines are being outlawed
Personally i would look for some secondhand gear to get you going which you could sell on again with little loss.
Music playback - Whats your goal with regards to cd playback, whats your style. If you just want basic playback then a twin drawer cd kit with controller would suffice. If you are more intent on mixing and dance music then a pair of tabletop players would be a better investment. If you do progress to laptop djing then a set of midi tabletop cd players are the way to go. More expensive in the short term but considering you may have cd/mp3/usb and software control it would be a good investment. A laptop setup will set you back well over £600 (laptop, external soundcard, dj software) and you would need a special licence to allow you to convert your cd collection to mp3 (£300 ish)
Lighting i would start with some scanners and moon flowers. The scanners get you movement around the room and the moonflowes give you some steady floor filling effect. 4 fixtures on a t bar would be a good start. No need for complex dmx for now as they have decent built in programs.
Soundsystem - this is where people struggle and faulter. The specifications of components can be misleading and you may think you are buying an amp that will fill a stadium but realistically it will be ok fr a pub functionroom. A 4000w power amp may actually only kick out 500w per side with one set of speakers connected. choosing a decent soundsystem is very important as no matter how good a dj you are a bad sound is a bad sound.
Have a look
here for some more info
some ideas of basic costings
basic cd mix kit - £270
amp - £240 (450w per side)
speakers - £300-400 (300 w per side)
2 scanner lights - £240 (250 w lamps)
2 moonflowers style l.e.d lights - £250
t bar stand - £50
deck stand - £50
extras (speaker cables, various audio leads, mic, speaker stands) £200
Thats just some basic kit and would in total set you back in excess of £1500 - if you want to go for better table top cd players that will control software when you get a laptop then the cost for these would be around £1000 - £1100 for 2 cd players a mixer and a flight case)
Then you would need pat testing which would be £40 ish, Public liability insurance (Get it from here for £75)
Transport and music - cant put a cost on that.
When you do invest all this money one thing you must not do is undersell your self. £80 a night sounds very tempting but realistically is a poor wage when you consider the time spent workig (a 4 hour gig = 7/8 hours usually) and business runing costs. Thats an aguement for another day.
I hope some of this helps and doesn't put you off. If you do need specific advice on any subject- just ask and somebody will reply.
Take you time and spend wisely
Best wishes
Dave