Here are a few free online resources:
Inter-City Baptist Media – Watch messages from Inter-City Baptist Church
Missions Mandate – MP3s on missions
Detroit Baptist Theological Seminary – Free resources
Church Works Media – Good place to find free music for congregational singing
ChristianAudio – Free audiobook every month
Google Books – Free downloads of books in public domain
Internet Archive – If you can’t find it at Google Books, try here.
Desiring God – Free pdf books by John Piper
Theologica – A free encyclopedia of Christianity.