Heavitas is free for personal use. But if you would like to use it for any commercial purpose, please donate $15 via PayPal by clicking the 'Donate to author' button, located below the download link. You would receive a confirmation mail regarding your purchase of the license for the font.
Heavitas has a new updated version, Heavitas Neue, with multiple weights, better kerning and variations in lower case letters. It can be purchased at https://www.creativefabrica.com/product/heavitas/ref/106/