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.

Rae

Drywall cutter from the hardware store/home improvement center for circles.