Autodesk - free Acad or Acad light demo good for 30 days after install and
then set your comp. clock back at 29 days and keep on going.
;D this is no problem if you dont use anything else that needs an accurate date.
Then you can get Bentley Microstation free internet download trial software 30 day demo and do the same thing. Hugh file and takes forever to download, but
again it is an easy to full demo - when it is almost expired, just set the 'ol computer calender back.
Autodesk sends you a CD that can be loaded ONE TIME ONLY on as many computers as you like.
Really, I just use MS Paint and i have drawn a calibrated master drawing with
a 1:1 n scale ruler built in that is more or less accurate to the nearest 2" or so. What are you designing? I have used this many many times for N scale structures, and my model quality has gone way up.
This is really easy to set up - just draw a few lines and plot and then measure the lines with a n scale ruler and then go back to the drawing and begin putting tick marks onto those lines and keep rechecking - it takes a while but
once you are done SAVE that drawing and with each new drawing make sure
you use SAVE AS so u don't wipe out that master scale.