what exactly is it?
i know its a browser but is it the same as everything else?

do you have to pay for it?
etc.

It's a browser written by Apple for Mac OS X. It's free and available here, although it comes with every new Macintosh.

It uses the WebKit rendering engine (the web rendering framework built into OS X and available to any OS X application), which is based on KHTML, an open-source rendering engine that is used in the Konqueror web browser.

so it doesnt work on windows?

Nope. It only runs on Mac OS X.