What I've been told is that you need an Airsoft license over here, and to get one you have to go on at least two skirmishes. Then you're looking at £60+ for a pistol. The gun I've been using cost me, overall, £14. The gun cost £4 from a Car Boot and was totally Orange, then I bought a Kobra Big Black spray from Amazon which was a tenner. You can see the results below;
Not perfect, especially as it needed touching up as some of the orange was peaking through, but for wider shots its fine. It also comes down to your painting method. My VFX guy swears by dry brushing it, which will give a more real look and you can start to texturise it. So its all down to your budget and how much effort you want to put in.
Oh and, of course, with no colour on show be very careful with where you're taking it (;