(Please see the attached PDF with photos of the basic supplies that might help you gather the best materials for this class.)

1 ACRYLIC PAINT SURFACE:
8" x 10" White Canvas (the type that has primed (coated white) canvas stretched over a wooden frame & stapled to the wood on the back is my preferred type - you'll also be able to find some that are stapled to the side of the wood frame.  (Other options listed below would work well, too.)

Options instead of the 8" x 10" White Stretched Canvas listed above:
8" x 10" Canvas Panel or Canvas Board  (It will not be as thick as the stretched canvas and will feel more solid like the canvas is mounted/glued to a stiff cardboard.)
OR an 8" x 10" piece of Acrylic Canvas Paper that usually comes in a pad of multiple sheets.

ACRYLIC PAINTS:   (not tempera, not watercolor, not oil)
Each child needs a variety of Acrylic Paint colors.  Although the flavor (color) of the ice cream is an individual choice of each student, they will all at least need White & Brown, Gray and/or Black.  It's best to also bring a variety of Blue, Green, Red, Yellow, Orange, Purple, & Black (even though your child might not choose to use every color).  Store brands in tubes are a good consistency.  

PAPER PLATE to use as a paint palette.

ACRYLIC PAINT BRUSHES in a variety of sizes.  Include a couple of medium size ROUGH Flat Brushes (looks like a square on the tip but bristles are rough and a little prickly to the touch.  Also include a couple of very small SMOOTH Acrylic Brushes (1 very small Round brush like a pencil tip shape and 1 slender Flat Square Shape)

WATER in a metal can, plastic cup or glass jar.

PAPER TOWELS