Ceramics Canada is my go-to for pottery supplies, and for advice on products and equipment. I bought my Shimpo wheel there, and I buy all my clay and most glazes and other supplies from them. They're also a hub of information for potters, always in the know about the local studios' services - even their kilns - and are able to provide really practical advice for students, hobbyists and serious potters alike. It's a technical and specialized type of retail, and they really know their stuff.
Ceramics Canada is fantastic, as a total beginner they helped me get set up with the right clay, tools and plaster to get me going on my ceramics journey
The staff at this store is amazing. They are incredibly knowledgeable and patient, and willing to answer my many, many questions to help me learn about pottery, glazing, and firing. No matter how stupid my questions are, they never make me feel stupid. They are an excellent resource! I would not be able to manage without them.