I heard this joke about plumbers. Plumber comes, client explains the problem, plumber takes out the wrench, hits the pipes in 3 spots, replaces one nut and asks for 200$. WHAT? 200$ for replacing a nut, complains the client. Well, yeah, it's 1$ for the nut, and 199$ for knowing what nut to replace.
It's a tongue-in-cheek version of a (unconfirmed, afaik) story about Picasso sitting in a cafe doodling on a napkin, when a lady recognized him and asked how much she could pay for the napkin, and he said $20,000. The lady protested, “But it only took you two minutes to draw.” Picasso replied, “No, it took me my whole life.”