My mom has had the same issue with her artwork. She is a muralist and fine artist. When people have asked her to paint a portrait for them, they are always amazed at how much she charges. They are used to Olan Mills "fake" paintings that one can get for less than $100.00. When she is asked to paint a mural or do custom painting in a home, they expect it to cost about the same as wallpapering. They don't even consider all the years of training and the level of skill it takes, along with talent, that has gone into what she does. This is why she mainly paints murals for the military and for businesses, because they can seem to be more understanding of her worth and are willing to pay the $$$ to get a one-of-a-kind mural or painting. (She has painted murals as big as three stories high and 300 ft. long.)
On a different note, I am amazed at how many people purchase those cheap quilts from Wal-Mart and then are surprised when they wash them and they fall apart. Then, they expect that a custom quilt should cost about the same, yet be high quality.