The simple truth is, you do not need to buy a curriculum for your daughter. I have homeschooled for more than ten years and have never used a curriculum. We use the library, trade resources with other families that homeschool, use the Internet, and set up classes and activities according to our kids' interests and abilities. I frequently browse sites offering used curriculum packages. Many of the sellers describe their used curricula as "like new" or "never used." I have to smile and think, "Well, there's someone else who is out $600 and learned the hard way!"
For practical ideas about getting started homeschooling your daughter, please visit our How to Homeschool Information Center. For a review of popular curricula choices, read Choosing a Homeschool Curriculum. Good luck!