We are starting a community site for budding authors. Here the young writers send a pdf files of there writing and we get them printed at a lower prices than other publishers. And these books are only sold through our internal network of shops. So I think we will not require any kind of Barcodes on these books. Experience publishers please clarify.
The purpose of the ISBN is to establish and identify one title or edition of a title from one specific publisher and is unique to that edition, allowing for more efficient marketing of products by booksellers, libraries, universities, wholesalers and distributors.
It will vary from each specific edition and publisher and it makes sense only if the book will be sold in open market. If your books will be only sold privately and do not need to be identified outside your own scope, there's no need to have a ISBN code.
Including, Amazon publishing FAQ is quite specific on this:
Do I need an ISBN to publish on Kindle Direct Publishing?
An ISBN (International Standard Book Number) is not required to publish content with Kindle Direct Publishing. Once your content is published on the KDP web site, Amazon.com will assign it a 10-digit ASIN (Amazon Standard Identification Number), which is unique to the eBook, and is an identification number for the Kindle Book on Amazon.com. If you already have an ISBN for your eBook, you’ll be able to enter it during the publishing process. Do not use an ISBN for the print book edition.
If they don't require it, I think it's pretty safe to assume you don't need it either but have in mind that not having an ISBN may have it's drawbacks if you, later, decide to change the way you sell and distribute books.
An ISBN is the book industry's standard "ordering number" for a book. If you want to sell a book through bookstores or most online publishers, you pretty much have to get an ISBN.
If you are only publishing through your own local network, and no one in that network requires an ISBN, than I guess you don't need one.
By the way, they're not that difficult to get. When I published my first book the publisher took care of that, but for my second book I got my own ISBN. I bought a block of ten so I still have nine for future projects. I just checked current pricing: In the US, it's 1 for $125, 10 for $250, 100 for $575, or 1000 for $1000. In many countries they are free. Getting them is no hassle. Again, speaking of the US, you just go to the Bowkers website, create an account, and give them your credit card number. You then use their web site to enter the title and author for each ISBN.