I avoid vending machines cause they cost too much. I plan ahead. For example I buy 12 packs of soda at the supermarket which comes out to 25 cents a can. I would take a can or two to school instead of paying $1 or $1.25 for a 20 oz bottle. If I can save $1 a day in a week that is enough for 2-5 gallons of gas.

Same goes for other snacks. Why pay 60-75 cents in the vending when you can get the same thing at Costco for 10-25 cents. Saving a few cents here and there can actually add up to $20 for a tank of gas at the end of the week.