Before ordering I recommend checking reviews online. Cathy Duffy is one of the most respected reviewers and has an excellent (and well-organized!) site.
Classical Education Books – offers a wide selection of classical curriculum books needed for online schools at a flat $10 shipping rate on any order.
The Learning House – family owned business with a wide selection of curricula as well as excellent customer service.
Canadian Home Education Resources – Many of the best resources that home school families have come to appreciate are located on CHER’s online webstore.
Maple Tree Publications – home-based business in Bradford, Ont. Produces fine quality Canadian and Charlotte Mason educational materials.
Rainbow Resource Center (based in the U.S.) Has one of the widest selections in homeschooling materials, but you will need to take into consideration international shipping cost. (however, it can often still be worth it).
Free Online Christian Homeschooling Resources
The Lee Familiy has developed Easy Peasy All-In-One Homeschool which contains a comprehensive online curriculum for math, language arts, science, reading, history and more. They also offer a separate site for high school students. And yes it is free! It was developed to support families who would like to homeschool but face time and money pressures.