Being an Ubuntu user for about 3 years, is it possible to obtain an e-mail address like firstname.lastname@example.org ?
If you became an Ubuntu member you get the benefit of an @ubuntu.com email.
Here is how you can become an Ubuntu member: https://wiki.ubuntu.com/Membership
Ubuntu members are people who are helping the development and growth of Ubuntu. It does not require coding or packaging. You can be an Ubuntu member by just contributing to translations or marketing.
By just using Ubuntu it is not that easy to get an email address.