Buying Isbn Blocks -

Bowker (MyIdentifiers.com) is the only official agency.

Library and Archives Canada provides ISBNs free of charge to Canadian citizens. Cost Comparison: Single vs. Blocks (US Prices)

Official pricing from Bowker rewards bulk purchasing, with the price per ISBN dropping by over 75% when moving from a single unit to a block of 10. Buy ISBNs | Bowker | Identifier Services