Getting started

Hi,
I know very little about steppers, but intend (time permitting) to
build
an NC woodlathe. I have been looking at controllers and they seem to
run
about $150 each.
What exactly do these things do? Are they just a glorified
transformer,
or do they have some intelligence? It seems that one could just fire a
series of pulses through a serial port and have them control a larger
current
which would run the stepper, or am I oversimplifying things?

I am also (this one may be a bit off topic) looking to have some laser
cutting done in 1/8" steel, but the place I have found locally wants $3
Canadian
(or $2 American) per linear inch of cut. This is prohibitively
expensive
as far as I am concerned, but is it out of line with what the market
will
bear? Is there any other way to do relatively clean cutting in steel
which is cheaper?

Thanks for any advice,

Simon