I have a lot of patients who have a spot at a flee market every weekend (often including Friday as well).
Most pay $8-$12/day, depending on the day and the location.
Most, it seems, don't care if they actually make any money (although they do prefer to at least break even).
One nice old man who sells knifes explained the reason. "It gets me out of the house, I've got some good buds there and it gives me and my wife some time away from each other."