Economically, you could use a piece of yarn. A safety pin. A paper clip. I have; i do.
Quite extravagantly, you can purchase (or make) beaded gems. Use discarded costume earrings.
Somewhere in the middle, you can purchase commercial stitch holders made of plastic.
Meanwhile, how about bobby pins? I recently went to a big box pharmacy store and for $2 bought 100 bobby pins, in the color of steel. Plain metal. Not shaded blonde, brunette, raven, redhead. Silver/metal.
I mentioned to the cashier that I was hoping to have found them coated in hot pink, or deep purple, or shocking blue...and she replied....paint them with nail polish. VOILA. What a great idea.
The beauty part of using bobby pins is that they easily slip on and off a stitch. Push on, pull off. No clasp to open, no paper clip to push together/pull apart, no yarn to fiddle with. Using them is akin to working a precision like spear....boom. Removing them; moving them - just as easy.
To transform them, I left a few of them on the original cardboard, and separated them. I painted them and left them for a few days to dry. I repeated this 3 times with the different polishes as shown.
So, do consider the humble bobby pin for your stitch holding needs. Here are some of mine, transformed. After adequate drying, its a good idea to slip them onto and off of folded paper a few times to break them in and allow any excess polish on the edges to transfer to the paper, if at all. You'd never want to ruin a project with color transfer, so do be careful. I do believe, however, there is likely little chance of harm. Over time, the polish cures as hard as can be.
My favorites are the deep red ones. The silver pins are unpolished, as purchased. I put these to work straightaway. :)