Tucson, AZ: $39,966

Income needed: $39,966

50 percent for necessities: $19,983

30 percent for discretionary spending: $11,990

20 percent for savings: $7,993

With the lowest total needed to cover necessities out of the 50 biggest U.S. cities, Tucson residents can likely make do on the $37,149 median income, which is just $2,817 short of the amount needed to live well there.