Any site you've created can be easily copied. Here's how.
Find and click the More button to the right of the site you want to copy.
Then select the Copy Site option.
Give your copy a name. This can always be changed later.
All done! You now have a copy that's ready to edit.
There are a couple of caveats:
The content of a blog is not copied to the new site. Blog content is specific to each individual site.
The only limit to the number of copies you can make is the limit to the number of sites you can have in your account. That number is 10 sites. So if you have 10 sites already, you won't be able to make a copy of a currently existing site unless you delete a site.