Mormons have larger families, so they probably spend more than your average American family, but it's spread across more people. So to compensate for the higher overall expenses, Mormon families try to reduce their "per person" expenses. In the finance industry we oftentimes do a rate/volume analysis. It's the same thing here. Mormon families "volumes" (i.e. kids) are higher, but their "rates" (i.e. how much they spend per kid) might be lower than average. But in the end the Mormon families spend as much or more than the average family due to higher volumes.

On the other hand, CBers seem to be extra sensitive to this frugality stereotype Mormons get. If you say a $25 t-shirt is too expensive, prepare to be ridiculed for being too cheap. It makes me chuckle. I figure we're all in different financial situations, so it's pretty unreasonable to try to determine whether another anonymous internet board poster is being too cheap or not