What is this?

I have decided that I am only going to spend $1200 for the year of 2010 on things that I buy (groceries, food, clothes, sundry items, etc). This is not including bills (like mortgage or electric) or gasoline for my car (although it will include vehicle maintenance such as oil changes).
This breaks down to $100 a month. Anything I get back from rebates will go back into the $100 and anything left over at the end of the month will get rolled into the next month. In the end, I hope to spend less then $1200 this year, it will be difficult, but I think I can do it.