I love this app/website so much. I use the computer version often, I have the android app and the j-crosswords app as well. I recommend Renshuu to anyone who asks me for learning resources for Japanese. And this is my top recommended resource for Japanese study. I love it. It's especially great because the format is actually really accessible for my ADHD, Autism and other disabilities. I don't know if it was intended to be like that, but it really is amazing, and one of the only resources I can actually stick to using. So I'd love to support the app as much as possible. But I don't have any money to support the app, so Is there any other ways to support this app that I've missed? I know there's also a discord community, but I can't use Discord so I haven't used that, sorry.
A good way to contribute to the app is by adding images and usage notes to vocabulary words that will help other users understand. You can also answer people's questions in the forums and add comments to entries in the grammar library. If you're fluent in any other languages, you could also help out by checking entries in the Translation Centre.
You'll have more opportunities to make those sorts of contributions the more advanced a learner you are, of course, so supporting Renshuu can be another motivation to study (:
I'm happy that you're here and enjoying renshuu! I naturally am grateful for those who can support us financially, but we specifically designed renshuu so that it is an option, and not a requirement.
Continuing to use it, joining in on the community activities, adding information like gillian described, telling others you know about it - those are all things that I truly appreciate people doing!