Books, materials, and curriculum all add up, and there are no tax breaks for home- school parents. There are ready-made curriculums available, but they are expensive. Many parents switch to homemade programs after the first year to save money and to give themselves more control. Look for recent textbooks in thrift stores, but make sure they aren't too outdated. History written just ten years ago may be filled with inaccuracies and may exclude women and minorities.
Science books outdate faster than they can be printed.
Reading books can be replaced with good novels if you can prepare lessons on them. Some school districts offer home-school programs that include textbooks if you are willing to work under their guidelines. If you purchase books from the publisher, allow thirty to forty dollars per text. A good library, combined with a good librarian, can be wonderful and trade books are usually more interesting than textbooks. Again though, you have to create the activities yourself.