I think children's painting has its own characteristics. If they don't want to spend too much money, they can prepare from another aspect, which can be that every sentence given to their children is accompanied by our teacher's evaluation and parents' language. This requires us to prepare in advance, evaluate from the perspective of children, and highlight children's innocence and imagination.
Now there is another way to scan children's works into the computer, and after simple modification, they will appear in the form of photos. This cost is not too high, and basically a small-scale photo studio can do it.