I've heard so many times "you use Sonlight...it's so expensive!" Compared to what? When you add up all the time I've spent online looking for books at the library, paying library fines, returning books, picking up books and scrolling through blogs and boards trying to find "the best" you start to realize that you've spent more time looking for stuff than acutally DOING homeschool stuff. So how can someone on a tight budget afford Sonlight?
Well let's start with budgeting. Do you have a monthly budget for homeschool supplies? Or do you use tax money? If you do, start buying gift certificates from Sonlight. Ask for gift certificates for presents. Even $10 gift certificates will add up.
Take advantage of their payment plans. They offer 3 month financing all year. During April they offer 9 month financing and during May they offer 6 month financing. Cool!
If you have to buy used consider buying the IG from Sonlight so you are still supporting them for the hard work they put into this curriculum. Then get the books from the library. You'll have to be pretty organized but it's doable.