RE: Cheap way to cut carbons?
I've cut mine on a table saw that had an abrasive blade in it. I made a small arrow holder that I could hold against the saw's sliding miter. I put a piece of masking tape around the arrow where it was to be cut and marked the exact length on the tape. The tape will keep the end from splintering.
I'm sure you could rig up something similar on a miter saw or a radial arm saw.