If your here to learn then the only thing important is what you have and what you want to do. Same for sharing what you've done or are doing.
If you are involved in a project of sorts
and want to share that info then
a link to another site should be appropriate.
If that link includes, in passing, that donations are welcomed, then it should be up to the individual whether that specific link is in keeping with this "sites policies" and post or not post.