Calculate Cash Saved

I just added a new calculator to the sidebar. Thanks to commutebybike.com! According to the calculator I am saving approx $2.37 a week by biking to summer school! Don't laugh...I purposefully picked that school so I could bike there quickly. I'm lazy, late and I like sleep! That $9 a month or whatever will probably go in my ice cream fund. How much are you saving? What will you spend the extra cash on?