Regional price differences are strikingly large, and have serious policy implications. The same amount of dollars are worth almost 40 percent more in Mississippi than in DC, and the differences become even larger if metro area prices are considered instead of statewide averages.
This tax map shows the real value of $100 in each state. Because average prices for similar goods are much higher in California or New York than in Mississippi or South Dakota, the same amount of dollars will buy you comparatively less in the high-price states, or comparatively more in low-price states. Using data from the Bureau of Economic Analysis, here's the adjusted value of $100, reflecting how prices are different in each state.
For example, Tennessee is a low-price state, where $100 will buy what would cost $110.25 in another state that is closer to the national average. You can think of this as meaning that Tennesseans are about ten percent richer than their nominal incomes suggest.
Adjusting for prices reveals average real incomes in Kansas to be higher than in New York, despite New York having much higher incomes as measured in dollars.