homemade plasmacutter i purchased off ebay for $400 dollars.
when using homemade plasma cutter sometimes its not as smooth of a cut because it needs smooth high frequency.
best way to cut metal with CNC. 50 watt does 1/2 inch and 100 watt does 1″ sever cuts without much back lag.
3 in one units are available for under 300 dollars on ebay tig/plasma/arc units. can be easily rigged up for CNC.
for larger tables THC (torch height controllers) are available for under $300 aswell. usually not needed for smaller flat sheets. manual control is easy with proper helmet when working on larger prints.