Brown Bagging It

Many of my co-workers never bring their lunch to work. Our office provides a refrigerator and a microwave so there is not a practical reason not to. I try to bring my lunch at least 50% of the time. I figure that it cost me $5 - $6 everytime I don't bring lunch. That really adds up ($50 to $60 a month).
The reason I don't bring lunch every day is that I am new to this group and I want to be social and make friends. Today it cost me $5.44 to be friendly. I would rather be friendly around a table in the break room but that is not an option right now. When I bring my lunch it probably cost me less than $2.
Once I get more friendly with the group then I will start brown bagging it more often...until then it is just money out the window.