The reformation cry was sola scriptura – by scripture alone, sola gracia – by grace alone and sola fide – by faith alone. And whilst at first glance these may seem quite obvious, the interpretation of what that may mean may be quite different from person to person. The scriptures and the way that they are used vary immensely from person to person and from church to church. I have so often sat with someone and found that we have quite different understandings of a single passage because of our culture and worship style.
This page has a great article about sola scriptura outlining some of the different views. It is only part one so check the site in a day or two for the rest of the article.