“How many examples” is two questions wearing one coat. The cost of another example is arithmetic you can do exactly. The benefit depends on what you believe examples are for — and the published evidence on that is more surprising than the advice built on it.
The cost side, exactly
Examples are input tokens on every single call, forever. Take a classification prompt whose examples run about 180 tokens each (input plus label plus the delimiters around them):
shots prompt tokens $/call @ $3/M in $/month @ 200k calls
0 420 0.00126 $252
