Free lunch

A free lunch is a nonexistent meal whose raw materials and preparation cost nothing, hence the saying "There ain't no such thing as a free lunch" (TANSTAAFL). Even if one receives a lunch as a gift, the giver had to incur the costs of production. And even if one plucks fruit from a tree, a cost is still incurred in land (the tree) and labor (the effort requires to pluck the fruit).