Yes, I did think about it. I have never seen any $ figures on the cost difference, and generally the 'green' treehugger types who push this sort of agenda only care about the 'green' and not at all about the '$'. One would think that if was really cheaper a lot of someones would be blaring cost comparison/savings figures loud and often to get the public behind it in a big way...and no one is.
Generally things that are 'better for you' seem to cost more, and for no good reason, either. Go to the grocery store. Anything that is 'healthy' or 'diet' or 'low ' is almost always more '$' than the 'regular' same item.