I've been trying to find this story for a while and I am having all kinds of trouble trying to find it. It doesn't help that I cannot remember much about it, so I'm hoping that someone can help and that what I do remember is unique enough for someone to be able to help me. I know some people don't like when these types of posts are made, but I don't know of another way to get help and I'll take this down either as soon as I get the story identified or some time has passed and no one has been able to help.
So the story is from the Harry Potter fandom. I'm pretty sure it's not a crossover since I don't particularly enjoy those. It took place during Hogwarts and I want to say it was 4th year or later, but I'm not sure about that. Harry bought study materials from the ICW (or maybe just from the ministry but I really thought they were for international tests) and they were linked to his magic (or blood linked? I'm not really sure how they were linked). Anyway only Harry could use the materials and Hermione kept getting jealous that she couldn't use the materials he paid for.
Now that I'm typing this up, the materials may have been for him to take additional classes outside of what Hogwarts offered and the materials included ways for him to write essays and get them graded.
I want to say that Harry got the idea from Neville, or he told Neville about it, and they both were taking additional classes. But I'm really not sure about this part.
As you can see, I really cannot remember a major plot point of the story that would be helpful in searching for the story. Any help at all would be amazing!