Proverbs 28:21
My father used to warn me of evil people saying that they would "sell their Mother for a dollar". As a young boy, it frightened me to view the person as sinister, no matter how fake their smile. When questioned, Dad explained that anyone who would quickly show favoritism would quickly choose to do wrong. Solomon describes it a little differently above but the jist is the same. Those who show respect of persons will sin for smallest of monetary values.
Only later did I realize it is not about the money but about human nature. It is our nature to sin unless God is in control of our lives. One aspect that changes when He is in control is that we no longer show respect of persons but rather show the love of Christ to all.
Are there areas in your life where God doesn't have control? If so, we are powerless to keep from sinning in that area. Only with God in control are we able to reverse the habits of human nature. Surrender your actions to God and He will prevent you from cheaply sinning.