Check out The CSI Project’s easy recipe for chalkboard paint. Make it any color you want! The recipe litterally costs just a few bucks. Would be great to recycle some old items into cool usable works of art!
You’ll need:
- Dry Non-Sanded Grout
- Acrylic craft paints
- Measuring spoons and cups
- Mixing cup or bowl
- Paint brush or stick to stir
Do It And How 
Even grout that doesn’t have sand often has other additives, like polymers that can be less than desirable for chalkboards.
Because it is getting more and more difficult to find grout that doesn’t have any additives, I offer these two options:
Powdered sheet rock compound. Drawback is in the quantity you must buy, just to get a few tablespoons,
Best readily available item I found is to use plaster of paris. Can get it in small quantities, and often already in the toolkit of many crafters.
Or, how about this one? Pulverize a piece of sidewalk chalk to a fine dust. (Use a common grater, or heavy sandpaper.) It’s calcium carbonate, AKA “chalk”. That’s the part of the grout useful to you, and that’s the easiest, least expensive option.
~DM
Thanks DM!