M.C.
Craft- picture frames. Pre-make or buy some cheap frames (if you find smaller ones, you can add ribbon to make it an ornament.) the kids can paint them. (I would buy poster paints, and 2-3 paintbrushes for each color...)
Game- Christmas relay. Wrap boxes to look like gifts, and buy Santa hats, cheap gloves, and make fake beards. (One set for however many teams you set up...) each kid has to run to the other side of the room where teammates will be waiting, where they have to switch off the "Santa" outfit and pass the present on. Then that kid runs back, and passes the gear to the next kid. Winner is whoever's team finishes first.
Snack- if you can do homemade, rice crispy treats shaped like trees. (Easy to make, and cheap. You can use mini m&ms for ornaments.) if it has to be store bought, I would hit up the snack aisle in Walmart and see if they have anything that looks festive.