From the perspective of taxpayers, this month was most notable for the April 15th deadline for filing state and local income tax returns. But just two weeks earlier, many California consumers also had the privilege of paying higher sales taxes. Although Californians pay sales taxes daily on their retail purchases, it can get a little complicated. For example, it can be imposed on purchases from out of state companies as anyone who shops on Amazon is aware. Also, some essential goods are exempt such as most groceries and prescription drugs. Forty-five states impose some sort of sales tax. Nationally, they...