8. Mill Valley, Calif.
Mill Valley lies beneath Mount Tamalpais, just a short commute from San Francisco. Its idyllic location is popular with many high-income commuters in the Bay Area. Less than 14,000 residents can afford to live in this 4.85-square-mile municipality, where the median listing price of a single-family home is more than $1.5 million, according to Zillow. Mill Valley residents have a median credit card debt of $5,110 with a $672 finance charge that will take 20 months and 26 days to pay off.
