There are a lot of naysayers in the personal finance space that scoff at the idea of giving up your $5 cup of coffee to build financial security. The $5 coffee seems to be the target of many F.I.R.E. bloggers. Why do we spend so much time on such a small thing? Because small things add up to big things! What does $5 get you? The $5 coffee or $5 breakfast sandwich adds up to about $100 per month if you are only buying during workdays. Since we are talking about retirement here the opportunity cost of the $5 is about that much less you can invest. Now of course…