Amazon is offering a free Echo Dot device to the first 2500 developers in the US who publish an Alexa skill between June 1, 2017 and June 30, 2017. Please see this page for full details.
No prior knowledge for Alexa development is needed. If you have programmed before, you can follow this tutorial to publish a skill in a few hours. I followed it and published a skill called Unofficial Wonder Woman Movie Trivia.