Everything below is a free resource found on the internet. None of these require any financial transaction of any kind.
Got Questions: My recommended first stop for all your random Bible questions. I do not agree with everything they say, but I agree with much of it and it is a good first look.
Bible Hub & Bible Study Tools: These two websites both have everything that standard biblical software products offer. You can explore dozens of translations and commentaries, see Greek/Hebrew, and a myriad of other useful study tools.
Blue Letter Bible: This website is much like the above two, but what I use it for and what the other two do not have is a searchable copy of the Septuagint (in Greek).
Systematic Theology by Louis Berkhof (Dutch Reformed). Not my favorite, but a free place to start. Systematics think through each doctrine.
Biblical Training I have never used this resource, and do not know everyone involved (professors), but a few names I do know such as Sean McDowell I trust.
Westminster Confession of Faith