Someone may have mentioned something along these lines already - I have yet to read everything here - but one of the biggest incidental money savers we've found is taking our own drink bottles everywhere.
Even if you only bought one 600mL carton of iced coffee every day, at $4 a pop that's $120 a month. A lot of small things like that - drinks, snacks etc - add up to phenomenal amounts very quickly with repetition. The bought drinks are unexceptional nutritionally and taste-wise as well. We make our own iced coffee / chocolate and use more actual coffee or cocoa, and less than half the sugar of commercial drinks.
We use the screw-top 700mL glass jars that Italian tomato puree comes in (shaped a bit like the traditional glass milk bottles but with a slightly wider neck) as our standard drink bottles - easy to spoon the dry ingredients into, and easy to drink from. We don't like plastic drink bottles and after years of trying to find ones made from a guaranteed healthy material that was also easy to clean, this seemed the obvious answer staring us in the face all along - and fits neatly into the car drink bottle holders - and even the bicycle drink bottle holders (although you'll need to stop to drink when using glass). Equally great to carry juice and water. We love cranberry juice, buy it in bulk, then 50:50 dilute with water to make it less sugary and more refreshing for on-the-go.
Snacks: We keep the glove box in the car (and a desk drawer at work) stocked with good-quality nut bars bought in bulk, along with ziplock bags of almonds, cashews, dried fruit etc bought in bulk, and carry mandarins and other easy-to-eat fruit, so that a snack attack will not result in lapses in the budget or the quality of our nutrition.
Work lunches and snacks are brought from home; we cook large quantities of soups and stews loaded with healthy and tasty ingredients, and excess is refrigerated or frozen in take-away containers for imminent or future work days. We make cakes with wholemeal flour, nut meal, and around 25% of the sugar of commercial cake, or apple/blueberry strudels etc, and slices of those go along for tea breaks. It doesn't take four times as long, nor use four times the gas/electricity, to make four times as much volume in the one session, and you only have one cleanup to do, and the spare food is so handy. People at work are always ogling at our lunches because they're so gourmet, but they're also less pricey than bought standard lunch fare. Win-win.
All our food is made from scratch - healthier, tastier, more economical. For anyone just starting out on DIY good nutrition, or wanting new ideas, Jamie Oliver just put out a really good recipe book called Save With Jamie which is all about saving time and money while creating wonderfully healthy and tasty food in your own home. I learnt a new strategy from him through that, of making one large roast (chicken, beef, pork, whatever) a week and super-sizing it for plenty of leftover meats for which he then has really zingy, 10 minute follow-up recipes that take the flavours in entirely different directions. This cuts down on hassle while keeping things interesting.