Affluent Roommate Cop Out?

So I don't want to have my character to have a super-nice job, but I'd like her apartment to be a little larger than the standard, and not have to worry about cash. If her roommate has an ill-defined job that would allow them to afford such a place (Providing that the roommate pays more of the rent), would that be seen as a cop-out or lazy writing?

Bare in mind that this isn't going to be a serious comic

When you say 'ill-defined job', why don't you just define the job? Pick a job that's generally well-paid, give it to the roommate, and it'll immediately seem a lot more realistic than being vague, and thus less of a cop-out.

There's also the possibility of the roommate owning the place and renting out a room to the MC. That could account for both the large size and the cheapness.

The best one is the "roommate" owning the place and renting it out.

If he just has a rich roommate who is renting the apartment and has the apartment just as much as the main character, then you need a reason as to why the rich roommate is putting up with somebody who doesn't pull his own weight.

Is this basically trying to justify the One Hour Workweek with "Friends" Rent Control?

Yeah it's basically to justify those.

By ill-defined, I meant more on the lines of mysterious. Like, the main character isn't completely sure what she does, but she knows that it's important.

I didn't think about the roommate owning the apartment, that's an interesting idea

If it's not serious, flagrant clichés and shortcuts are fine. Otherwise, you wouldn't have anywhere to hang all those lampshades.

You probably will need to work out why said affluent roommate is OK with the arrangement, though. It certainly happens; a friend of mine lives with a woman who's a trust fund kid whose living accommodations are automatically paid for and thus my friend has no rent to pay or anything. However, what the housemate gets out of it is a dog sitter, company, co-conspirator and a 50% share of housework.

Indeed, and, provided the MC and the roomie are close friends, such an explanation could work. Sure, the MC doesn't pay much, but they provide company and they do chores and maybe cook every once in a while.