Some confusion there.
To generate the program you need a CAM package, of which Mastercam is an
example.
The post processor, as the name states, will process this program to be
understood by your CAM machine, therefore it will depend mostly on that.
Most CAM packages have some basic post-processors for most machines, but
nothing like a trial.
I suggest you generate paths for one of your parts on various CAM
packages and post-process them in resin or maybe wood (for speed).
Be wary of who you buy from. From experience, you'll be spending a few
moments with them to fine tune things for your methods/machinery.
--
Rui