Parents may choose to teach their children at home for many reasons -- from believing public schooling is inadequate to wanting to teach their religion as part of the curriculum to needing flexibility due to frequent cross-country moves. Whatever the reasons, homeschooling parents may find that there is a lot of material out there that costs a ton of money. However, homeschooling doesn't have to be expensive. In fact, it can be incredibly inexpensive, even free, if done with the proper frugal mindset.
Use the internet. It's a modern convenience that homeschoolers of twenty years ago didn't have, and its powers are amazing. Obviously, not all the information you'll find is reliable, but if you do your double-checking (keep a reliable source handy, such as an encyclopedia), you can find lots of useful activity ideas, tests and quizzes, reading materials, and contacts.
Use your library. We may be moving rapidly into the purely digital age, but books are still a handy way to get information. Hopefully you have a library card -- it's a must for frugal media consumers -- and can check out tons of great books for your children. Design a history, science, or literature curriculum and pull all the materials from your local library.
Utilize used book stores in your area. Your children will not learn math any better from a 2010 textbook than they will from a 2000 textbook. Sure, there may be more graphic depictions of arithmetic, but if your youngster learns best a certain way, you should be the one to provide the resources for them to do so, not a "more modern" book. Textbooks are really only best for the sample problems they provide, and since math hasn't actually changed in ten years, you can pay $5 for an old book instead of $100 for a new one, and end up with the same result.
Have an apprenticeship mindset. Hundreds of years ago, children weren't formally educated -- they were apprenticed off to someone to learn marketable skills or a trade they would use for the rest of their lives. Today, we focus on a broader education, but in the micro picture, you can still use an apprenticeship mindset. Talk to people you know (friends, relatives, acquaintances) who have useful skills you'd like your child to learn, and ask if they would be willing for your kid or kids to shadow them for a day. Your child can learn a lot more about animal biology watching a vet at work than learning in a classroom setting.
Take advantage of flexibility and incorporate lots of real-life experiences. Your kid doesn't need to be sitting at a desk for seven to eight hours a day, so use that time to take them out into the field, so to speak. If they are learning about the Renaissance, take them to a Renaissance fair. If they are learning about ecosystems, take them to a swamp to study the wildlife. Many of these experiences are free and fun for your entire family.
We've got a ton more frugal tips, plus lots of other topics you might be interested, over at our blog.