One of the fasted carvings that I have found is to carve hotplates. They are standard in size being 6 1/2 x 8 1/2 inches with four rubber feet on the bottom. They sell for $20 each and sell like hotcakes...
I have made different hotplates for various sports teams, depending upon my location for a show.
Here's one example:
These are pure profit.. as I have no material costs other than a few minutes and paint.