Jack Tar

come from a Cracker Jack box

To obtain or retrieve something that is useless, cheap or fake.

jack in

To stop doing a regular activity, such as a job or studying.

jack of all trades

One competent in many endeavours, sometimes regarded as not excelling in any of them.

jack of all trades, master of none

A person who has a competent grasp of many skills but who is not outstanding in any one.