Piss Poor

 It's a myth that the phrase piss poor came from the days when people used to sell their urine for use in tanning. If you had to sell your urine you were piss-poor. It's true that urine was once sold but that is not where the phrase came from. It was first recorded in the 1940s long after they stopped using urine for tanning. The word 'piss' was added to words to strengthen or emphasise them e.g. people might say piss weak. The phrase piss poor has nothing to do with selling urine.