Chalkboard-alike wall for children
Having met a few attempts to use chalkboard paint (couldn't tell you the brand) I'd strongly suggest looking for a (used/surplus, assuming cost is a factor) chalkboard, it will work much better. Somewhere within 50 miles of you there is almost always a school being either remodeled or abandoned; or you can leave that part to an architectural salvage firm and buy from them (it will cost more.)

If using the paint, I would suggest applying it to a sheet of tempered hardboard (e.g. Masonite®) rather than directly to the wall surface.