Everyone is concerned about the regressive nature of sales taxes. One place that the regressive nature of point of sale taxers would actually use market forces to help the poor is cigarette taxes. It has been shown, no I don't have the reference, that youth are very price sensitive to cigarette prices. Smoking rates are higher in the lower SES. It seems that jacking the price of cigarettes with a higher national tax would actually achieve health benefits that would accrue to the poor more than other groups.