Honto is giving away a large selection of their eBooks (including manga, light novels, novels, magazines, etc) for free to promote their eBook business for a limited time. Some popular titles include “Your Lie In April (四月は君の嘘),” “Attack on Titan – Before the fall (進撃の巨人),” “Rurouni Kenshin (るろうに剣心 )”. They are mostly first volumes, but a great selection nonetheless.
For full download list, click here: http://honto.jp/cp/ebook/recent/free.html. For any catergories you’d like to view more of, click on the text “無料の電子書籍をすべて見る” underneath that section.
Honto’s eBooks are readable on PC, iPhone, iPad, and Android by downloading their proprietary app. Here is the download and details link to their apps: http://honto.jp/ebook/dlinfo. Mac is currently not supported so I cannot guide you past this point. I have a post of what works and what doesn’t from my previous findings here: https://kaizora.wordpress.com/2014/01/03/honto-jp-ebooks/ and a follow-up of someone getting it working here: https://kaizora.wordpress.com/2014/02/24/honto-jp-ebooks-legal/
Either way, they’re free; no strings attached. All you have to do is add the eBooks that show up as 0 yen in cart, and go through checkout. (It takes 2 clicks). Afterward, you can access them by opening up the honto app on your device and it should show up on your shelf.