Some of the best supplies and prices for them can be found at one of my favorite websites, Fire Mountain Gems. They always have great prices and it seems like and endless supply of everything I need. So, check out http://www.firemountaingems.com/ and see what I mean.
Some of my best selling pieces have been made from supplies from this awesome site. I hope that I have helped some of you find things you haven't been able to get for a good price.
I am always open to suggestions for great supply sites, so let us know who you think is awesome!
Take care, and happy shopping!