Amazon offer a self publishing option called
Kindle Direct Publishing. Amazon will take 30% of their royalties but other than that there is no cost to the organisation & Amazon will take care of DRM.
To prepare the book you need to use their
Kindle Create software. The standard Kindle format needs to be imported from a doc(x) file, the print replica format can be imported from a pdf but interactive elements such as video, audio, hyperlinks won't be available on iOS, Macs or PCs.