Whether or not you need an ISBN and barcode depends on why you wrote the book and who the target audience is. If it’s a collection of your grandmother’s memoirs you’re publishing, with the intention of sharing the book with the family, then you probably don’t need to have an ISBN or a barcode.
If you’re publishing your business expertise, with the hopes of increasing your credibility and recognition, and intend to sell the book online, then absolutely, you should have both an ISBN and a barcode.
Think of the ISBN as a social security number for your book. It’s a 13 digit unique identifier that identifies one specific version of your book. (And if you offer your book as a soft cover and a hard cover both, you will need two unique ISBN numbers.)
You can purchase both from Braughler Books or at Bowker.com. If you purchase them through us,  we’ll also handle the registration for you.