These plates are actually chargers that she purchased at Michael's for less than $1 each. (I believe they were on sale and she had a coupon.) The paint that we used is just regular craft paint, which can be wiped off if the kids make a mistake while painting, but needs to be handled carefully afterwards because it may chip off.
Other than that, the kids were pretty much left to their own creativity to finish the project. To layer the paint, we let it dry so that the wet colors didn't bleed. We started painting early afternoon, did that off and on, and then let them dry for about an hour before school ended. All of the plates were dry and ready to go home that day.
I've seen a lot of similar chargers on clearance lately, so I figured even though Christmas and the whole holiday season has passed, it was still worth sharing. With crafts like this, I try to keep the cost at around $1 per student, so this stays right within that budget.
**PS ~ Rather than have parents donate specific treats for our Christmas party we had them donate money (any amount) to cover the cost of pizza, drinks, and the craft supplies. I gave all of the money to our room mom and she did all of the shopping. We had enough to feed everyone and even had some money leftover to put towards supplies for our Valentine's party!