I am strictly a hobbyist - my day-job is designing audio-visual systems (and running a team of other designers).
My machine cost me £3k used about ten years ago, and came with the machine itself, a Bosch router, a handful of hold-down clamps, and a PC to control it. Since then I've spent about £300 on rebuilding the control box (the original caught fire!), about £100 on better hold-down stuff, and £400 on a new fanless PC. Plus fancy collets, some specialised bits, and so on. I have upgrade plans too, but they'll probably never happen.
There are loads of options for software, but generally you'll need CAD to design the thing you want to make, CAM to generate the tool paths from that, and machine control software to actually wiggle the router around.
I use Rhino3D because that's what the chap I bought the machine from used, and I get on well with it. That's a grand per version; I'm still on version 5, version 7 is out now. Upgrades are cheaper, as are education licences (I have a staff card for a university I do day-job stuff for; the Rhino people were perfectly happy to accept it). Then CAM software; I use MADCAM which is £800 per version, again with various discounts. Finally there's MACH3 which controls the machine, that's about £150, or MACH4 is out now for a bit more.
I'd think very carefully before buying one if you need it to pay for itself - it's completely doable, but you go from being a woodworker to being a CAD and CNC person, and it's not the same. I really enjoy it, but it's very different from taking a particularly good shaving with a plane, or turning a bowl. And there are loads of places that'll make you things from paper drawings faster and cheaper than you could do it yourself.