About the only thing I will buy at a craft fair are the crocheted nylon scrubbers.
I like to look - and see how things are priced.
I am also getting to the stage of life where I'm not buying much "stuff" any more.
I have seen a few items where I would have been very willing to pay for the instructions on how to make them - a casserole carrier, for one thing.
I really don't know how people even break even on the cost of their supplies - much less make anything for their labor.