since I'm writing a story where Rody and Deku journal, my hc:
post cannon, when Rody lives with Deku, and Deku is a famous hero, Deku gets Rody a Paper Republic portfolio in cognac. Rody isn't used to having disposable income, let alone expensive things, and would never get it for himself. But Deku has watched as Rody has become a big fan of having somewhere to get his thoughts out privately. And he has a couple of notebooks now, but he doesn't have a lot of ways to protect them (not that he'd be too bothered by wear and tear). Regardless, Deku put a lot of thought into what to get him. And I feel like Rody would prefer pocket notebooks, so really it'd be less expensive for Deku than if he had a bunch of A4's or something. And he makes sure Rody knows to help him feel better about the expense. Rody has gotten used to Deku buying him notebooks for more than he'd personally spend, but a whole portfolio makes him a bit overwhelmed- with appreciation of course. Also with worry, but he makes sure to use it every day, and it even gets a patina fast.
Rody ends up asking why he didn't get one for himself since Deku has a much more chaotic lifestyle than he does at this point. But a. after Deku's notebook got damaged by Bakugo in middle school, he welcomes the wear and tear since it reminds him of where he came from. And b. he remembers that he was the first person to get Rody a gift in a long time when he gave him his first notebook, and I like to think he realized gift giving is a love language of his, but he doesn't want to just give meaningless gifts that would do nothing but worry Rody. So he chooses things that would be really personal and important to him.
Rody, as a thank you, starts a notebook that Deku is allowed to read without asking for special permission. He leaves it on their nightstand. It's not his deepest darkest journal entries, but it's earnest notes that he makes about life and love.