There are options that can keep costs down, if you choose to use them. When we began homeschooling we spent very, very little. Each year we have purchased some items , but only because I wanted to, not because we needed them. Spending on curriculum should be done prayerfully, even if you can afford it, because many items are purchased and not used. Books can be resold, but usually for a fraction of what has been paid for them.
Christians are sometimes cautious about the library.
But if you read-aloud, you can skip over objectionable parts. Recently I discovered that Charlotte Mason, in her book, A Philosophy of Education, also suggested this skipping of anything not appropriate for children. You could even skip the book entirely. If a book that you are reading has an anti-Biblical view, such as evolutionary theory, you can discuss what the Bible does say. Children need to know opposing thought to better defend the faith and become independent thinkers.