Slightly off topic, but the point was brought up.
While I point no fingers, nor do I attempt ridicule or any other form of offence, over population has ALWAYS been one of societies greatest problems. For a thoughtful and well articulated (though somewhat repetitive) work on the subject you might read the classic work by T.R. Malthus entitled “An Essay on the Principles of Population” (Available on Amazon). Other than the fact that population can now be controlled by modern contraceptive methods, everything in this classic 152 page essay written in 1798 is still true today. In fact as oil and food prices continue to rise the problem of feeding over seven billion people will likely become untenable. As gruesome a thought as it is, I would not be surprised to see half a billion people starve in third world nations by the end of the decade.
As for the original question. I am sure someone at your income level has already found ways to cutback. My suggestion would be to find a way to increase that income with a side business. Go to yard sales looking for bargains to sell on ebay, learn to cut hair for other low income families, put up filers for house cleaning, , mow lawns, anything you do well someone will likely pay you to do it.
