There are many places to purchase homeschool curriculum. Here are some resources:

Online at Christian Book Distributors or Amazon.com. Do a search for "homeschool" to search for a particular item; click through the link and purchase online. 

Through the links on my website. If you see something you like, click through the link and purchase online.

Through the links on The Checklist Assistant. Do a search to find what you want; then click through the link and purchase online.

Note: If you purchase through my links, I'll receive a small referral fee that helps me keep this website ad-free. Thank you in advance! (see Affiliate Links for more info)

Local education stores - ask friends or look in a phone book (Do they still make these?!)

Curriculum Fairs and State Conventions - This is a link to a vendor who supplies "goodie" bags for homeschool conventions. Click on "Homeschool Events" then "Event Calendar" to see when a convention is coming your way. Do a google search for that organization for more information.

Through curriculum publisher's websites. Do a google search for publishers for more information. 

Cindy's Products:

The Checklist, The Checklist Assistant and more.

Discovery Store has a variety of educational games, DVDs, science kits, models, and and electronics that make homeschooling much more FUN! 

Discovery Channel Store

Teacher Created Materials is one of my favorite resources for thematic history and science Unit Studies, as well as composition workbooks:

Over 1500 products from Teacher Created Resources