Until recently an OK commentary from 2014 covering the entire Bible incl. the Deuterocanon (Fortress Commentary on the Bible (2 vols.)), cost $51 on pre-pub and spans over 1,750 pages. I tried to get the word out about it. At the moment it's not on a sale. EDIT June 23. 1:47 PM local time: OliveTree has Fotress Press Commentary on a sale until Monday next Week, it's not the same software as the better one though:
https://www.olivetree.com/store/product.php?productid=26938
Until today June 1. You can get the
Sheffield Bible Guides (44 vols.) for $109.99 - that's a lot more money and it's not nearly as recent and it's not a verse-by-verse commentary but more like introductions. However,
the main problem is that these are in the wrong software - it does have lots of resources in the Store but that can be a temptation, and I recommend Accordance instead.
Of course, You can go wrong with these resources too, but they are probably better than
most 19th century commentaries that
many people use. I've heard arguments that resources to get started should be free - in that case all You can have if You need to cover most of or a large part of the Bible, are severely outdated and deficient commentaries and introductions. Even if You look for temporarily free books that is going to be true. At very few occasions great books on small parts of the Bible have been offered for free.
I know most people are definitely not ready to spend around a hundred dollars on a Bible plus a commentary or introductions - what price point is fair has been discussed at length at a Bible Study software forum. Also, some won't read from a computer monitor or tablet and I understand that. If You have a very small library (up to 50 books) on the computer and/or a tablet the main benefit is merely that You save on postage costs - and that may make much more of a difference outside the U.S., Canada and the U.K. And of course some simply won't afford just like You pointed out.
These are the couple of resources I was able to suggest - and the prices didn't last forever, as some of the least dangerous resources for preferably under a hundred dollars and they are not perfect solutions as the software, Store and marketing have many deficits: such as unclear how to install and update it, some of the versions are slow, aggressive marketing, and indirectly supporting things (other books) that are offered such as scholarship that has been proven wrong. But what I mean by this is that a purchase (if made at the right time) may still be a more secure way of getting interpretations and background knowledge than trusting a small group Bible study each time. I'm not saying that small groups are always wrong, not at all, for example I had a good experience in May last year - there was someone (who at the time for a very short time was a friend) who read the original language and I showed her Amos from the Hebrew Bible, a long time after that while researching I found something really exciting in the passage which I would have overlooked if it weren't thanks to her.
Thanks for responding!:
A single version of the Bible is never going to provide the depth of knowledge others desire/need, but for others the importance isn't in the words of versions past and present, original texts or anything else. The importance is in their interpretation of the words presented before them, coupled with the teachings of their peers.
Really focusing on building knowledge and understanding of Biblical texts, not just your individual faith as it fits into Christianity as a whole but the actual texts, is a whole different level. It's a good level to be at if you're that way inclined, but the majority of believers are reliant on verbal interpretations made by others. For a long, long time the majority of people who believed could not understand any existing texts, they were reliant on other people spreading the Word of God via the spoken word. There are people who are still reliant on this, the physical Bible itself, in all its wondrous versions, being something for academics and serious scholars.
That's not necessarily how it should be, but we always have to factor in that now everyone is willing/capable of undertaking the sort of focused research even amateur theologians undertake.
