Also in the US, also buy from MessySupplies. They are in the UK, I last ordered from them in May of last year (I still have a small quantity of green xanthan gum and the envelope it shipped in, postmarked May 2, no recollection of how long it took to get here)
Quite a few of the 'gunges' use a food thickner or similar as a base. And the colour is typically some form of powdered paint. (children's art product). Even if you can't find a direct supplier, you'll still be able to mix your own. Ebay, and Amazon would be my first stop, also Walmart or any commercial/wholesalers might stock something of interest.
There was a thread on here a month or so back, showing a leaked photo with the supplier for Nickelodeon's "studio paste"- in this case a drum of ready mixed gunge, but they might ship the dry stuff too.
The other gunge is the various 'Slime Baff'/'Geli Baff' products. These are fun if you like a translucent free-flowing stringy gunge that slides off the body.
Thanks for the feed back! I was just looking for a way to get the shipping charges down. Looks like I'll order some stuff from LiquidX or Messysupplies for a session. I would like to keep the money in the group if possible. Just wondered if I missed a vendor in the U.S..