#4 Rebel Robin by A.R. Capetta
Robin Buckley, sophomore at Hawkins High School, has tried all her life to fit in. Now, all she wants to do is stand out in some way. Deciding that she wants to spend the upcoming summer in Europe, she focuses on who to bring with her and how to make the money she requires. But her small circle of friends is more interested in dating and pushing her to date as well. Of course, the twist is, Robin herself hasn't figured out yet that she likes girls instead of boys, but we who have actually watched Stranger Things already know this. The book takes place during Season 1 of the show, but the events are barely footnotes in the overarching story (ie: Will Byers goes missing, is declared dead, returns from the Upside Down but since he's not in Robin's circle, his story is merely background noise to Robin's). It ends, of course, during the Season 3 events, with Robin getting her job at Scoops Ahoy, where we wind up meeting her in the show.
An okay book, nothing overly special or even interestingly insightful. But as far as "spinoff" books that usually wind up being completely awful, I was pleasantly surprised at how decent and how spot on it was to her character.