http://www.everythingairbrush.com/
This store stocks a wide range of airbrushes, compressors, accessories and spare parts. Pricing is reasonable on most items, better deals can be found but for convinience of it all being under one URL I like them.
Have a good look through what they sell to get an idea of the kinds of items you might be looking for. They do kits made up with an airbrush, compressor and some paints etc and all the items individually.
Cheap brands of airbrush should be perfectly fine and workable for starting out with, and indeed are just as capable as the several hundred pound models of airbrush. What you tend to get for more money is quality of craftsmanship, like maybe the trigger mechanism will be notably smoother, or the dismantle clean and rebuild operation might be easier going etc. Another thing that costs money is decent quality micron tips (0.15mm or less) which is'nt what you need for spraying acrylics onto mini's, I would reccomend a 0.3 or 0.4mm nozzle setup, gravity feed, dual action airbrush with a 2ml or a 5ml paint cup. %
ml doesnt sound like much, but 5ml of properly thinned paint can basecoat an entire unit, and you will likely not need more than 5ml very often on a job unless its large job! Larger paint cups only add to the weight of the brush and block vision a bit, get as small as you can work with for best results, 2ml is plenty for most occasions.
http://www.everythingairbrush.com/acatalog/Gravity_Feed.html
Theres one in this list for £19.20,
AB-130 which should be more than sufficient and do you proud as a starter brush, if money is no object, then I quite like Harder & Steenbeck Evolution airbrushes, my current brush is a 0.2mm H&S Evolution Silverline and its quite beautiful to use if I'm honest.
For an airsource, this will probably cost you more than the airbrush;
Something with a tank is better than without, a piston motor is better than a diaphragm. Get an inline moisture trap aswell as the manometer/trap that is usually on the output of the compressor.
http://www.everythingairbrush.com/acatalog/AS_Series.html
these are basically the common place chinese ones, theres an
AB-AS186 for £91.91 that would do absolutly fine for a long time to come. I'm running a 196 which has twin pistons but is otherwise the same, the tankless ones work okay too, but they get hot and spit moisture after 15-20minutes of solid working, while the one with 3L tank runs happily for me for an hour to 2 hours (because the motor gets a rest each time the tank is full) after that its spitting moisture a bit too much to spray antyhing well.
Noise levels allow me to run it indoors int he day time, but it would keep people in my house awake a night,neighbors wouldnt hear it as I'm in a detached house, its not exactly deafening but is definatly not what I'd call quiet, My 2HP 24L tank compressor out in the shed makes 50times more racket and could be heard several doors up the street.
for paints, Vallejo do a model air range that I hear is quite nice, but all the brands of acrylic paint you know of can be thinned out for spraying, citadel thins lovely for me using Liquitex Airbrushing medium and nothing else.
http://www.artsupplies.co.uk/item-liquitex-airbrush-medium.htm (theres a similar sounding product from Golden, but I havent tryed it as this worked great the first time) Other possibilites are isopropyl alcohol (tamiya thinners) or vinegar free glass cleaner (automotive window cleaner - vinegar corrodes chrome which is the coating on the airbrush)