Found this while searching craigslist:
"Casting slip for plaster molds. 180 gallons available in 2 gallon boxes @ $4 per box."
This link should take you there. If not, it was posted yesterday "under arts and crafts". It's pretty cheap and I am planning to get some...so save me a little bit :)
Happy New Year!
Cookie Jars - One
2 hours ago