I’ve found that on Yahoo.jp they have some manga you can (legally) read for free. Of course not an extensive collection but of reading for practice then content sometimes less important. They seem to have a reasonable collection.
I’ve also been reading Webtoons. Fans have translated from the original Korean into many languages, including Japanese. Downside is that there is no furigana (some of us still need that crutch!) Currently I’m reading 神の塔
I’ve also found you can download samples of Japanese language books for Kindle. I’ve got some Harry Potter. You only get a few chapters but at my pace of reading that is still plenty!
I like Bookwalker a lot for this same reason - they have weekly/monthly offers where you can download free manga or novels. Great way to build up a library for reading practice.
It was created by Ken Akamatsu who did Love Hina. It’s mostly out-of-print, non-mainstream stuff, though. But you can find some interesting stuff there that you might never have stumbled across otherwise.
You’d be surprised! Maybe a crazy shounen with lots of weird vocab might be a little difficult, but I’d recommend reading something a bit more slice-of-life, maybe with a school or office setting. If you’ve been studying grammar, by level 24 it’s definitely possible to try reading some simpler manga.
I can’t really read for fun yet, but I try to parse sentences, check with Google or an official translation, and I usually get the gist. A lot of the grammar goes over my head, but I was never formally taught English grammar and I picked that up by being around English speakers, and reading. Like, a lot. Yeah, I was THAT kid.
Maybe take a look at some of the beginner book clubs on this very site!
As long as you find a manga with furigana you should be able to. Have you downloaded Tae Kim’s Japanese Grammar? I’ve found that very useful. Practice is the key, even if at first you are not understanding that much.