How do I obtain a copyright?

How exactly do I go about obtaining a copyright for something? Do i need to pay for it? If so how much?

Start here:

http://www.loc.gov/copyright/circs/circ1.html

IANAL, etc.

Got here. In a nutshell, any original work you produce has inherent copyright protections. This site will tell you how you can make it for lack of a better phrase, more formal.

Copyright Basics includes:

How to Secure a Copyright

The above and the following are from the U.S. Copyright Office; their FAQ

To obtain a copyright, you must create something. Under the US Copyright Act and the Berne Convention, copyright is inherent in the act of “fixation” (the process of converting creative content into tangible form).

However, in order to get a legally enforceable copyright, you must register the work. In the United States, this requires filing certain paperwork with the Copyright Office (a division of the Library of Congress), submitting one or more copies (or other depictions sufficient to identify the work, in the case of a unique work such as a sculpture), and paying a smallish fee ($20 in the typical case).

Mailing a copy of your work to yourself by certified mail is not a sufficient means of securing copyright, although it will establish proof of date of fixation. You cannot sue on a copyright until you have registered it, and your remedies are limited if you do not register promptly after publication.

KellyM has the answer most in accord with my education in my Copyright Law class lo those many decades back. The above link by Scarlett is pretty good too.