Pay-before-hand's never weel ser'd.
The tradesman is said to be troubled with two kinds of bad customers, viz., those who pay in advance, or "before-hand," and those who do not pay at all.
Pay him in his ain coin.
Pennyless souls maun pine in purgatory.
Penny-wheep's gude enough for muslin-kail.
"Penny-wheep," says Jamieson, "is the weakest kind of small beer, sold at a penny per bottle;" and muslin-kail is a common kind of broth. The proverb expresses that poor service merits poor reward.
Peter's in, Paul's out.
"Spoken when, after we had wanted a necessary person a long time, upon his arrival, another equally necessary is gone."—Kelly.
Pigs may whistle, but they hae an ill mouth for't.
Applied when an awkward person is attempting to perform some work of which he is incapable.