Spending $25 on some books at the thrift store seems like a bit much, until you price these materials new. We have a full curriculum for sixth grade reading once I buy the workbooks. Even these would not be necessary, but greatly enhance the experience. I just love Bob Jones stuff, but it is usually very teacher intensive, so I don't use it in every subject. In the pile D purchased are also some ABeka books, pieces of various science sets, a social studies textbook and a health curriculum complete with teacher and test manuals and the test answer key. If I decide to use these, I just have to buy the workbook$ and away I go. I might just wait until next April or so and go to a homeschool convention and try to find them used. If I can't find them used, I can order from the ABeka booth and get free shipping. :)
I enjoy buying certain staple items new, but reading-wise, our entire collection is pretty well cobbled together thrift store finds, McGuffey readers and the good old King James bible. I also use www.crayola.com and print colouring pages for the flags of the countries we study in social studies. I also like the Dover sticker paper dolls and colouring books we used during our brief overview on Japan.