You can purchase Curtis' music digitally right here on this page (latest release on the left!), or purchase physical copies on his bandcamp page. it is also available on apple music, amazon, spotify, etc. but you should know that buying an album once helps an independent artist considerably more than streaming it hundreds of times.
Curtis usually receives the most revenue if you buy an album here on this page, or buy a physical copy from him at a show or through bandcamp.