So, I've enjoyed Arioto/100 days and I've just gotten into the light novel version of Buying a Classmate. They seem to have similar premises, but are also pretty different, and I wanted to blather about it without filling the Buying manga thread with tons of spoiler bars.
So if you clicked here by mistake, shoo. Spoilers for at least the first few chapters of Classmate.
Right. So Arioto seems pretty straightforward. You see how the deal starts, and the motivations make sense: Mari wants more money and was already flirting with the idea of selling her companionship; a 'bet' over not falling for a girl seems like easy money. Meanwhile Aya is a rich predatory lesbian out to corrupt and seduce her for fun. (What's actually going on might be different, but that's where it starts.) And, going on, Aya's enjoying herself, while Mari wants the money... and is maybe also enjoying herself more than she wants to admit.
While with Classmate... we start in media res, though the start of the arrangement gets flashbacked in short order. But even with Miyagi's POV the motivations seem obscure. Like even to herself, it's just something she did on a whim. The girl getting paid doesn't actually need the money. And neither one seems to actually enjoy the interactions that much, unless both girls are overly competent at lying to themselves.
We do start getting glimpses, though. Miyagi seems to have real friends at school, though they don't come up much outside of it, but her home life is dead and lonely: mother 'gone', father working all the time. While Sendai does have a family life but doesn't like it, toxic parents who keep comparing her to her older sister. So despite having nothing in common (except a growing taste for ero manga), nothing to talk about, and annoying each other a lot, Sendai provides Miyagi with something like companionship and gets a safe-ish space to hang out in return.
It kind of makes sense. But the energy is very different from Arioto...
An interesting point regarding their friends: Miyagi's friend Maika remains a character as the story goes on, while Sendai makes new friends in college and her high school friends are pretty much never mentioned again.
