In the supermarket the other day I'm looking for something to get for lunch and I see a nice pizza on the shelf for £3.50 then just as I'm about to put it in my basket I see that it's one of those buy one get one free offers but here's the fallacy. I only want one. I will not have time or the inclination to eat both before the second one goes off, it will just sit in the fridge while I'm away on an excursion.
So why do supermarkets do this? If they want to shift stock why not make it half price instead of 2 for 1? It makes absolutely no sense and all it does is piss people off who are on a tight budget because they cannot benefit from the deal and they actually sell less of that item.
You might well say seeing as you were going to buy one anyway why not just get two and be done with it, you haven't lost out? The point is that you are being given the shaft so you don't bother buying any at all. People who actually want two will be getting a deal while you are definitely not.
I'm also making a poll on this to see what you would do.