Here is an example of a formula that returns a different price for each of several kinds of fruit. The data type of the result is Number.
case ([Fruit Name], "Apples", .5, "Pears", 1, "Berries", 4)
If the [Fruit Name] doesn't match any of the cases, null is returned. To return a default value when there is no match, add one more Number argument to the end.