You need a simple CNC Device with all steppers and so on?
http://www.amazon.de/dp/B00MAXHPC6 ~ $600
Ok, you get this CNC only with steppers. You need also a CNC Controller (i.e. GRBL or TinyG) with stepper drivers.
Does this thing really do steel? It goes down to 5k rpm and I hear steel should be around 1,500rpm but big horsepower.
It will do steel even RVS. There is a correlation between the RPM, the size of the cutter, the feed rate and the max plunge. I used an example that is also on youtube with the following params. Milling tool diameter = 3 mm, 10000 RPM feed is 120 mm/min.