Mary Jane Watson and Peter Parker are both working-class characters in Spider-Man — and this is, as far as I know, always true across adaptations as well — but there is definitely a very gendered way in which the Spider-Man fandom expresses classism against them for that, which is especially evident when looking at how fans talk about them regarding their relationships with characters who are richer than they are.
I’ve seen many fans — both the usual douchebro fanboy types and a lot of women — call Mary Jane a ‘gold-digger’ for dating Harry Osborn, ESPECIALLY in the first ‘Spider-Man’ film directed by Sam Raimi. Many of these same fans will then cheer on Norman Osborn for basically calling her a slut who just wants Harry for his money, even though he’s the villain and it’s blatantly not true, re: why she’s dating him. And now with TASM2 coming out, people are bashing her for being a trashy working-class girl who’s going to ‘steal’ Peter from classy, fashionable Gwen.
Peter, on the other hand — I’ve NEVER seen anyone call him a ‘gold-digger’ for dating rich uptown girl Gwen Stacy. In both the 616-comics and TASM, Gwen is explicitly affluent — she lives in an expensive apartment in a rich part of town (courtesy of her big-shot lawyer mother, according to the TASM DVD commentary), her father in the comics belongs to the same rich man’s social club that JJJ and Norman go to, etc. Peter, on the other hand, is obviously working-class and is constantly in financial trouble.
Yet no one in fandom accuses him of being a gold-digger who’s only dating Gwen because he wants her money. If anything, he gets praised for dating well and having good taste in women. And likewise, no one calls him a gold-digger for being married to Mary Jane when she’s a successful model and actress in the comics, when she is presumably making more money than he does.
So basically, the classism in the Spider-Man fandom definitely comes out in gendered ways, and fans are constantly shitty about Mary Jane in really gross discriminatory ways based on her gender and working-class background.