The cost of living in the US varies greatly depending on the city and state of residence. The US South and Midwest tend to have the lowest cost of living, while Hawaii, New York and California top the list of the most expensive states.,The margin between these extremes can be quite high. Mississippi – the least expensive state in the US – has an adjusted COLI (Cost of Living Index) of only 83.3, while Hawaii tops out at 193.3 and New York at 148.2.