I took a class where the instructor let us use her seam sticks, and it worked great. Hers were not covered in canvas, just plain, unfinished wood. When she said that they were $15 apiece I almost fell over.
A few weeks later I made a stop at Home Depot's molding department and found a length of rounded molding with a flat back. I had to ask three different workers before I could ascertain that they would sell a one foot piece. I got some funny looks when I explained to the man who cut it that it would be a sewing tool, but I walked out of the store with my seam stick for $3 and change. I had to sand the edges when I got home, but it was easier than cutting a closet rod in half.