<prompt> Human: I barely use my credit cards, have a good credit score and I am always bombarded with 0apr offers for 12 to 18 months. I have thought about using part of my credit limit to invest in stocks, preferred stocks or Bonds. My train of thought is : is it smart or stupid to gamble with money that costs little. Has anyone else thought about it ?  <response>: gambleThats exactly what it would be, at least for 12-18 months. Gambling. The market could tank in that time, and youd be left with a large bill and little to show for it. 