Fill in this joke please

[hiflier]

A joke I heard some time ago involved a farmer who was fed up with people entering his fields and picking his fruits. So he put up a notice saying 'PICK YOUR OWN!' This of course had the opposite effect. So he finally twigged that he could actually entice people to come in and pay for the produce they had picked. Hence he put up another sign. But he worded this in such a way as to put people off coming to his farm. The problem is that I don't know what the well-known phrase or saying was that he used. Anyone got any ideas?

[redpenner]

You pick it, you own it