I work at my old "real" job every Tuesday. It is my treat day and I usually buy my lunch (rather than a vegemite sandwich!). Yesterday for some reason I decided to buy a souvlaki. It was quite nice, some chicken, lettuce, tomato and tzatziki sauce. $8 and gone in 10 minutes.
It really pointed out to me a reusable cloth nappy which is used a couple of times a week is not expensive at $20-30. For $32 I would have only 4 souvlakis and about 1kg extra weight! It really is a matter of keeping things in perspective!