You might spend more on "wants" than you think. A threadbare minimum of warm clothing is a need. Anything beyond that, such as shopping for clothes at the mall rather than at a discount outlet, qualifies as a want. Yes, the rules are tricky, but if you think about it, they make sense.
Just remember that being self_employed means that you must also pay the self_employment tax, so include this in your calculations. The self_employment tax is double what you would pay in Medicare and Social Security taxes if you were employed.