You don't need a business licence to get an ISBN. You can buy one under your own name, using your SSN if they need an official "business" number. That runs about $100.
If you use CreateSpace or Lulu's free ISBN, then you still completely own all the rights to the book. The only thing that changes is that in the database that only the book store stockers use, the book is listed as being published by CreateSpace, whereas if you buy it yourself then you can choose your own publishing name or your author name to have it listed under.
I bought one myself for the first book I published, but then decided it wasn't worth it. Since then I've used one of the free ones. They still let me put my publisher name inside the book, so the only person who sees the ISBN number as attached to that company is the people who order it to put it on Amazon and places like that. The individual customers/readers who actually order the book to read it won't be able to see any difference between the $100 and free ISBNs.
Hope that helps!