What is the saying/quote from the Bard, that in effect says 'giving one's opinion is too costly for any purse to bear,' I wish to be able to quote it correctly.I believe it's a famous quote 

Expert Answers
Kristen Lentz eNotes educator| Certified Educator

You may be thinking of Polonius' advice to his son Laertes in Hamlet.  In act I, scene III, Polonius offers some last minute pointers to Laertes before he leaves to sail.  In the midst of Polonius' long blessing, he offers this advice:

"Take each man’s censure but reserve thy judgment.
Costly thy habit as thy purse can buy,
But not expressed in fancy—rich, not gaudy,
For the apparel oft proclaims the man" (I.III.69-72).  
Although Polonius warns Laertes about reserving judgment, the line "costly thy habit as thy purse can buy" is actually shopping advice on what kind of clothes Laertes should purchase.  Polonius' advises his son to buy the nicest clothing he can afford, but to avoid anything too trendy or flashy.  In other words, clothes make the man!
Another line from this lengthy speech that does address keeping your opinion to yourself is when Polonius suggests:
Give thy thoughts no tongue,
Nor any unproportioned thought his act.
Polonius basically advocates keeping your thoughts to yourself and not being too hasty to act.