You need to be careful with people that have nut allergies, when considering stuffing your pincushions. I use silica sand.
Available at Princess Auto, in small quantities and much more reasonable than in the Craft stores.
I make a small cotton bag using egyptian cotton (more threads per sq.inch), adding a layer of wool bat to the cotton fabric, after I have stitched down the wool batt, cut out the pattern, leave an opening and fill it with silica sand (which is glass beads, used generally for sand blasting), then hand stitch up the small opening. The wool batt helps to keep the sand from escaping from the inner bag.