What is the easiest way to cut foam board and what do you use to cut it?
I always get jagged edges no matter what I use.
I use a jigsaw. It was about $20-$30. Used for cake stuff only.
I use an exacto knife. If the edges start tearing I know it's time to get a new blade.
I use a hot knife--basically a hot exacto knife. You can google it to get an idea of what's out there. Mine is by Walnut Hollow.
Drywall cutter from the hardware store/home improvement center for circles.