I have received many emails over the years from people asking where they can buy dominoes in bulk. Despite this, I decided to remove all links to any suppliers from my web site. Sometime in late 2015, this page itself will be deleted.
The reason for this is because I have no personal experience ordering from any retailer. I cannot vouch for the quality of a product or a company's customer service. I do not want to unknowingly steer anyone towards a negative experience.
I know this may disappoint some people looking for domino supplies. Trust me, I've been in your shoes. My brother and I didn't make our own dominoes because it was fun. It was because we couldn't find a large amount of inexpensive dominoes either.
The only recommendation I can give is to contact other domino topplers. Ask them if their happy with the product and service they received. Just don't ask me.