BibleGateway.com, BibleStudyTools.com, BibleOnTheWeb.com and Biblica.com all offer free versions of the Bible online. As of 2015, these sites offer various options including audio, downloadable text files, videos and commentaries.
BibleGateway.com offers various versions of the Bible in over 40 languages. Audio versions of the Bible are available here, as well as reading plans and an individual passage search option. The website has an app available for download for Apple, Amazon and Android devices.
BibleStudyTools.com also contains multiple versions of the Bible along with other features, such as dictionaries, devotionals, Bible study programs, videos and blogs are available to aid in research. The site also features a daily Bible verse and inspirations.
BibleOnTheWeb.com features different versions of the Bible, as well as an option to read multiple translations of Bible passages simultaneously. It has a plan for reading the Bible in a year and a section that answers some Bible-related questions.
Biblica.com is the official home of the Bible's New International Version. The site has an option for reading along with audio files, as well as a study version of the NIV Bible. The NIV Bible is offered in multiple languages, and the site includes an FAQ section and help pages to help readers understand the book's teachings.