ssorenn is exactly right. Where I am right now (Durham, NC) I could rent a goddam mansion of a house (5 bedroom, 3.5 bath, built in the last 10 years, good neighborhood) for ~$2,000 a month. To buy it, probably a half million at absolute most (though I haven't looked into those prices).
So lets say after taxes you're at $90,000, after house payments at $60,000, health insurance at $45,000. Those are some rather sweeping assumptions I've made, but you can fairly easily support 4 people with $45,000 in disposable income.