Welcome to the forum :)

Yeah... this is quite a time-sink (and potentially money-sink) of a hobby.... ;)

Based on your post title, I'm guessing you were thinking of grabbing one of those pre-made Chinese jobbies off ebay?

They get an awful lot of flack (from me too!) but I think they do actually have a place; as long as you're prepared for how pathetic their capabilities are, they're a reasonably inexpensive way of experiencing the CNC process and way of thinking, allowing you to start exploring what you might want out of a machine.

The Shapeokos of the world give the same lessons, but are more expensive to begin with, although probably allow a greater amount of time before you outgrow it.

My first CNC was a simple conversion of a 3D plotting tank (think 40x40x40 work area, but about as stiff as jelly). It taught me lots about GCode, CAD CAM and what I needed from a machine.