everybody – to keep things to oneself, not to tell what should not be told is very necessary; but falsehood is not the right way to conceal things that have not to be told, the right way is silence.Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 1
Fragment ID: 13726
Because one is dealing with dishonest people, that does not justify one in going down to their own level.
If you think that the prices are too high, or, simply, if you want them to be lower, you can say so and ask for a reduction, but it is not right to support your demand by a false statement.
No one is bound to speak the truth when it would be harmful or to speak whatever is in one’s mind; it is always permissible to keep silence or evade a reply and not to say what one does not wish or think it right to tell. But to tell a lie is superfluous and not justifiable.
It is usually out of weakness (mind and vital) that people lie; those who are strong in nature do not need to lie. A sadhak has to be strong and not weak – straightforward when necessary, silent when necessary, but not a liar. Straightforwardness does not mean of course that one has to babble out everything to everybody – to keep things to oneself, not to tell what should not be told is very necessary; but falsehood is not the right way to conceal things that have not to be told, the right way is silence.