Mom and I thought "STITCH MARKERS!" at the same time. Small elastics work for knit or crochet as row markers, too - knit/crochet them in place, snip them out when you're done.
We spent about 15 minutes this morning sorting 1200 rubber bands (metallic! neon! glitter!) by color.
And now we have six sets of markers for whatevs. The green and orange are mine, the purple for our friend Lynell, and the pink, blue & yellow are Mom's.
They'll probably only last a year, two at the outside, but not bad for two bucks!