Sure, go to www.dot.tk
and register for a free domain name, the homepage is the best place to start, it gives you a box check the availability of the domain name you want.
When you have completed the registration, confirmed your e-mail address etc, you'll be taken through the process of setting up your domain name. Select the option to mask or redirect to another domain and put your current website in the box.
As stated by the previous reply, it is only a redirect and sharing done directly from your site will result in facebook blocking it, the only other solution, is to set up the domain name, create a new account on 000webhost using your new domain, make a back up of your current site then restoring it to the new account and using your new domain name.