Tortillons and Stumps
Tortillons and Stumps are the tightwad blenders. I used to see them for a nickel or a dime each in boxes next to the cash register at my college bookstore. I wondered what those little rolled cardboard tubes like pencils without leads were for, until a drawing class put them on the supplies list and I learned to use them with graphite and charcoal.
Tortillons are the hollow ones that have a single point. Stumps have two points and are rolled solid, they can be sharpened in a pencil sharpener. They come in various sizes from different manufacturers and are usually made from a gray fuzzy heavy paper. The picture below shows three tortillons in different sizes and one small stump posed on my black hardback sketchbook cover for contrast.
Tortillons and stumps are still relatively cheap. It's $2.99 for a class pack of a dozen each large, medium and small tortillons at Blick. Stumps cost a little more each, you only get 3 of each of four sizes in a pack for $2.56 but that gives six points each size and they last longer because they can be sharpened. You can also make your own by rolling printer paper or scrap paper if you want to be super tightwad about it.
Keep them organized by color groups after you've used them -- warm neutrals, grays, yellows, reds-oranges, greens, blues, violets. Orange doesn't usually need its own stump because it vanishes into reds, but you may want a clean one in a light orange if you don't want to redden it too much. They are so cheap it's easier to keep half a dozen for different color areas than to try to clean them off after use.
Because they come to a point, tortillons and stumps are useful in the same ways as a Taper Point Colour Shaper. The happy thing is that they're loony cheap and available anywhere, so this is something you can try for cleaning edges and applying very small bits of color before you get any fancier tools.
Tortillons sometimes collapse on themselves when they're old, first losing the sharp point and then just flattening. You can poke it through again with a bent paperclip or just use the solid stumps instead, reserving blunted ones for blending large areas.
They do wear out, but it takes longer than I ever expected. So this is the low price alternative. Blenders of one kind or another are important in realism because of the need to push color into tight areas, mix it on the page, edge up hard edges or soften others and place color in smaller amounts than you could with the tip of a stick.
One of the great things you can do with tortillons and stumps is something I discovered with graphite. It applies just as much to oil pastels or any other medium you're shading with them. Once they've been used and a color is on the point, you can shade carefully with just the cardboard blender to achieve very soft, light shades of the color. A deep red could be a softly applied pink with this method.
Also, using a used stump or tortillon for adding color means that you're more likely to use enough texture to fill the grain of the paper and have gentle, soft transitions. Shading with them takes a little practice and you may have to scrub it into a patch of color more than once to get your softly shaded areas worked out just right, but they give immense control. The pointed tips let you get into very small areas with soft shading. This is great when you're using oil pastels with hard ink lines or other mediums where you don't want them to cover opaquely or have strong broken color.