For anyone out there who is into paper crafts and does lots of scoring and X-acto cutting, here is a great idea for a DIY scoring tool that is easy and totally works:

Open up a paper clip and snip off the smaller rounded end with wire cutters. Lightly hammer the cut ends to flatten, insert them into the open chuck of a craft knife handle, and tighten firmly. Voila! A nice alternative to the bone folder, and really good for scoring heavy card stock.