Tilesetter has two options, a Lite Version which is completely free to use, but you are limited in what you can do. The other version is the full version which you have to pay for.
Link to page to download: Tilesetter – Downloads
Tilesetter is an application that automatically makes an autotile faster than you can make it.
I would recommend the Free Version because I have only used the free parts of Tilesetter. You can only make two autotiles. If you are familar they are both called Build Borders (Blob) and Build Borders (Wang).
To download, click the corresponding download button that correlates to the operating system being run. Once downloaded, Extract the file to a safe version, then you can execute the application.