My plan is to use StepCraft mainly for plywood 2D cutting.
What CNC software do you recommend?
It must be easy and cheap.
It must input SVG or PDF file format because designs are made in design programs.
I assume you mean the machine controlling software.
Stepcraft used to send WinPC-NC Starter with the machine. This a nice program to get started in learning how to
operate your Stepcraft.
Later you can upgrade it to a full version or switch to an other program.
Personally I like WinPC a lot and it has never failed on my SC-420.