Is a CNC machine in your future?
I see a never ending stream of questions about buying a CNC machine. Usually people ask about a CNC router. Most don't have a very clear idea of what they want. But the real disconnect is what kind of budget they have. Hopefully after reading this, you will have much better sense of what you can get for your money. There are some emerging tiers.
These are very low cost machines, almost exclusively from China. Typically, they are called 3018 because they have a work envelope of 300mm X 180mm (12" X 7") or similar. They use a low power spindle and stepper drivers. The sellers make many compromises to keep the price low. It often ships with a pirated copy of Mach 3 but some ship with a Grbl based controller. Is it actually usable? The sellers often claim it will cut wood, plastic, aluminum, copper and brass. These generally cost in the range of $250 to $350 US Dollars.
There is a second tier of these machines, often called a 4030 or 3040 for the 400mm X 300mm (16"x12") work envelope. They have similar construction to their little brother 3018 machines. Prices run roughly double the 3018 machines.
One of the things to watch out for is shipping cost. Some of which are surprisingly high. I have seen some offers where shipping more than doubles the total cost.
The Middle Tier
These machines tend to be bigger, often 1000mm X 1000mm or even larger. They typically have aluminum extrusion construction, V Wheel rails and are designed to take a small router as the spindle. Some use linear guide rails. There is a mix of belt and screw driven. Honestly, I don't know why people keep desiging routers using belts. The control electronics are often Grbl based though the Chinese versions frequently sport a Mach 3 breakout board and an unlicensed version of Mach 3. Example brands are Shapeoko and X-Carve. The WorkBee and Lead Machines fall into this category as well. Costs are higher too. They range from $1200 up to $2500 for the "pro" versions.
From here, as you move up market the distinctions start to fall apart