This is a short list of my favorite online study Bible environments. I call them “environments” because they are not just a webpage with the text of the Bible on them. You can log in to these webpages (if you want). They have all the content of a print study Bible, just online. Everything is searchable. You can also make your own notes, highlight passages, etc.
NET Bible – This is hands down the absolute best study Bible environment available online. All the NET notes, Dr. Contstable’s notes, articles from bible.org, Greek/Hebrew tools, parallel versions. All totally free.
HCSB Study Bible – All the contents of the HCSB study Bible for free + Greek/Hebrew tools.
ESV Study Bible – The basic environment is free with Bible, searching, highlighting, etc. If you want the study Bible resources or the Greek/Hebrew tools, you have to purchase them as additions. The study Bible resources can also be activated for free with the code included in a print copy of the study Bible.