Bible Gateway: Read the Bible for free in dozens of translations.  Also, free commentaries are available to explain passages of the Bible.

Got Questions: A very helpful site to ask questions about God, the Bible, and life from a biblical worldview.

The Gospel Coalition: Hosts many blogs and resources available from pastors, scholars, and Christians around the world.

Desiring God:  Sermons, articles, and free books from the ministry of Dr. John Piper.

For the Church: Gospel-centered resources from Midwestern Seminary

Gospel in Life: Blogs, sermons, and other resources from the ministry of Tim Keller.

Christian Counseling and Educational Foundation: Articles, videos, and resources on a variety of issues from a biblical perspective.

Be Thinking: A collection of articles and media related to understanding and defending the Christian faith.

Monergism: An archive of sermons, media, articles, websites, and free books written by Puritans and authors from a reformed perspective.

Ligonier: Great articles, videos, and other resources from the ministry of R.C. Sproul.

9Marks: A ministry that helps pastors and churches think biblically about churches and leadership.

The Joshua Project:  An informational site about all the people groups on earth and the Church’s progress on reaching them with the Gospel of Jesus.