I remember doing a craft like this with my grandma when I was younger. Painting with marbles didn't require any "new" supplies. Everything I already had in my cabinet.
bowls for the paint
box large enough for the papers to lay down flat and tall enough that the marbles won't escape
freezer paper-to lay papers after painting them so that they don't get paint on your counter/floor
pour about a teaspoon of paint in each bowl. We used 4 colors. The purple seemed to really dominate so we started to use it sparingly.
put 1-5 marbles in each container with paint and roll them around until they get covered in paint
then dump the marbles in your box and roll them all over your paper that has been placed in the bottom of the box.
We experimented with different amounts of marbles from each color. We also did one color at a time or 2 at a time. Or even all the colors at one time.
This is definitely something fun for people of all ages. It was lots of fun to see the different patterns and to see which papers were everyone's favorite!