The best free alternative to Adobe InDesign is Scribus, which is also Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to Adobe InDesign and many of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to Adobe InDesign are Canva (Freemium), Polotno Studio (Freemium, Open Source), Desygner (Freemium) and Lucidpress (Freemium).
A DTP app that stands out with: 1 - One click export of fixed-layout eBooks in two popular formats: EPUB3 and Amazon KF8 (Mobi) formats. 2 - Styling modeled after CSS3. 3 - Superior multiple-page viewing capability. 4. Intuitive and easy to use UI.