Well those of us that live here can say this city can be expensive especially with all the money attracting others to the area we end up paying a heftier price for being here already. 

bestplaces.net has calculated the cost of living and gives some insight to the question of "why is Missoula so expensive". They use a 100 point scoring system so if Missoula scores below in that category it is less expensive and over 100 means more expensive.

Out of all the categories ( groceries, health, housing, utilities, transportation and miscellaneous) we only scored below 100 on one and that is utilities which is shocking as Montana has a high utility cost but I guess compared to all other states we are less expensive but only on that one thing.

Overall we scored 110 our of 100 bringing us to be an expensive city to live in.