GotQuestions.org
Do you have a question about God, Jesus, the Bible, or theology? Do you need help understanding a Bible verse or passage? Are there any spiritual issues in your life for which you need advice or guidance? Got Questions has over 10,000 questions answered.
BibleRef.com
A free online Bible study site. Their goal is to provide easy-to-understand discussion of the Scriptures, without relying on jargon or slogans. Here, you can find book-by-book, chapter-by-chapter, and verse-by-verse commentary on the entire Bible (eventually).
EnduringWord.com
A free Bible commentary that can be searched verse by verse. It was created by David Guzik.