Oh, i don't interact with the needs system at all. That shit is garbage. I just cheat to keep all of my bars full.In order to advance one day, you basically need 2 sources of food and water, which means you have to spend somewhere between $24 and $64 a day. Except that most quests reward you with about $5 (and the photographer questline is long, but a finite amount of money). It's excessively difficult to save up for the more expensive quests (like buying all of Evie's clothes). Although, at the same time, the fancier stuff you buy is worthless; you can buy computer parts, but they're not really implemented, whereas the adult toys can't be manually used, and are rewarded/used for the end of the photography questline.
As for the cashier, I think she means 'Here's your receipt" because she says it when you buy something.
That being a side-job wouldn't be very surprising though, but obviously it isn't done yet.
Before the photography job or the janitor though, it feels like the actual classes should have been the first thing in, because that's what your day as a student is structured around.
Everything else is secondary.