Just realized most people budget wrong by ignoring their true hourly wage

Everyone talks about cutting out coffee to save, but they miss the big picture. I started calculating my real take home pay after taxes, commute costs, and work clothes. For my job in Chicago, that's about $22 an hour, not the $30 on paper. Seeing that number made me stop buying a $15 lunch because it costs almost an hour of my actual life. Now I pack food and that hour stays in my pocket. How do you figure out what your time is really worth?