PT Barnum has been credited--erroneously, it seems--with saying 'There's a sucker born every minute.' I will take that one step further and say that there is at least one customer for ANYTHING that someone wants to sell. If you don't believe me, look at Craigslist or Etsy--OR have a garage sale.
I have had a few garage sales in my time, but not enough to consider myself an expert, by any means. BUT, when I say that people will buy ANYTHING, I mean that literally. Not only have I sold books and audio tapes and VHS tapes and household goods, but I have actually sold bottles of spices that were half-full. Yes, people will buy used spices. I haven't tried to sell used bars of soap, but I may the next time I have a sale. I'm sure someone will buy them.
So, with the idea that people will buy anything, I have come up with a product that will probably make millions: hypoallergenic, fragrance-free perfume. I know, I know, you laugh. But think about all of the people you have ever known. You done? Now, defy me by NOT finding one person who would think this is a good idea. We ALL know that one person who is so ditzy that she would buy this product by the gallon. And if each one of us can think of one person that would buy this perfume, I KNOW I could make millions of dollars selling it. :D