The kind of budgets people will come up for you when they want you to move to an expensive town. The name comes from the fact that the people are only factoring in basic expenses such as rent, utilities, and maybe a car payment. This assumes that you live like a monk or nun, because they seem to figure that you never go out and eat very little or not at all.
I was duped into moving to that fancy resort town by being shown a budget that made it look like I could afford to live there. This was a true monk/nun budget because as soon as my car broke down I was out of luck.