I use thin PCB and a $30 paper cutter from Office Depot. Been abusing it for about 6 years now, and it still cuts paper just fine. Must be self sharpening, as I use it for thin metal as well. Turned out to be a very useful tool, like the $44 drill press.
The paper thin PCB etches and drills faster too. I don't use large, heavy parts, high voltages, or really care if it looks professional. Just as long as it's functional, besides who is going to see it, once it's in a case?