Finding the goods can be tough.
Here is a brief list of my current favorites:
Soller composites: great selection, good price on cloth and Uni , mold releases, etc.
US composites: good reliable inexpensive epoxy
McMaster Carr: Massive hardware selection
Fiberglass supply : Lots of goodies
Other good ones I have used with great luck :
Thayercraft: cloth
Aircraft spruce: wow! build your own airplane
ACP composites: Many specialties
CST sales: Good but expensive
Chinook: barrel nuts
Ebay: Large assortment, haha. hit or miss
Please share your favorites.
thanks , Dirk