Know I'm late to the thread but Woodland Direct carries Simpson Dura Vent and ICC under their own brand. I dont know if their pricing is any better than anyone else but they have by far the best chimney configurator on the Internet. Even better than the Chimney MFG's. Just input your info and it will give you the BOM. Really impressive.
http://www.woodlanddirect.com/Chimney/Chimney-Systems
http://www.woodlanddirect.com/Chimney/Chimney-Systems