Wait....you have never heard of Paperclay? Paperclay is an air dry modeling medium that is water based and can be cleaned up easily, dries in 24 hours and works a lot like clay. You can make your own, there are several recipes on the Internet that use easy to locate materials, but I can not testify for their quality. I have used a variety of brands but I personally prefer one from School Specialty. It is Sax Paperclay. As far as the cost per student and per project it really can vary. I spend less than $4.00 per 1 lb block of paper clay. The students use what they need, put back what they don't. We have used it to create all kinds of sculptures, jewelry pieces, ornaments, figurines. Anything you really can think of.
A few tips:
1. You can use solid Paperclay to mold an object or you can apply it over an armature. We usually apply it over an armature of newspaper and tape covered in Plaster gauze.
2. You can recycled the Paperclay if it has dried out by soaking it in water. You can create slip if you use more water than Paperclay and stir. Although, you will be stirring for a while.
3. Use water to attach the paperclay to the armature, also a wet sponge or papertowel will help to smooth out the texture.
4. Apply it in thin layers so it doesn't crack. It doesn't crack normally but if it is too thick all that moisture has to get out somehow.
5. You can sand the Paperclay to smooth it out but it needs to be wet sanded.
6. Acrylic paints are fantastic to finish it off with. Just apply them in thin layers so that they don't get too glossy.
If you try it, please let me know what you think!