So I'm building a type of guitar that already has a patent on it. I had the idea originally but went online to see if anyone else had come up with the same idea and yes the invention had already been made but I've heard I can buy or borrow a patent as so I can use it to call my own without having copyrights on me.
The patent owner could grant you permission to make, use, or sell the invention.
This isn't the same as getting permission to call it your own, and it is completely separate from copyright.
I've heard I can buy or borrow a patent as so I can use it
The term for borrowing a patent would be to licence it. You would contact the patent holder and get a licence from them to use their patent. This is a legal agreement between you and the patent holder outlining what you can do with their protected idea, and what you are to give them in return. You should not enter into this kind of agreement without the aid of a lawyer.