What Does The Phrase "One And Done" Mean?

In a "one and done" deal or package, you get or do everything in one go. So a one and done insurance policy, for instance, would consist of a single one-off payment, with everything probably in one document and requiring only one signature.

The full sentence, from which the phrase comes, would be something like: "there's just one (payment, etc) and then you're done."

The idea is to make transactions simpler and less time-consuming.