This is a great thread, with lots of ideas.
The best trick I learned is to mention in passing to people who garden how much I love fruits and veggies. This seems weird, but I always find that people who garden have tons of stuff they want to give away in the summer and not enough people to give it to. So, they remember me and brings over tons of stuff. Then, I just chop and freeze and can. It makes them happy to share their green thumb talents, and makes me happy because nothing beats fresh veggies.
Mostly, I buy frozen bags of veggies and even some frozen mixed fruit for adding to yogurt, etc (berries) when most fruit is out of season.
I buy alot of pears, they have the highest fibre content of most fruit yet are cheap.
I purchase the cheap tins of soup (the ones you add water too), with reduced sodium, then just add a bunch of my frozen veggies, some onion, and any leftover ends of fresh veggies.
Pasta noodles are very cheap. I buy the whole wheat ones, then just portion it out and mix it with the frozen veggies to bulk it up.
For juices, I water them down by at least half. After awhile, you get used to it, and you start to prefer the watery version. Plus, you are getting less calories, sugar, and more water.
For lemon/Lime juice to add to water or cooking, I just use the little bottles you buy for a dollar with the fresh lemon juice in it.
I do not buy organic fruits and veggies unless the fruits are such that I am going to be eating the peels, or they retain alot of the chemicals (for instance, I buy organic strawberries because I cannot peel them but don't do so for apples). This cuts down on alot of cost. I would love to buy everything organic ... but it isn't possible.
Milk .... I buy fresh milk for cereals and drinking. But, I use the powdered milk for coffee, baking, etc.
I don't buy fancy sauces and stuff anymore ... but, when I open a can of spaghetti sauce, I will freeze it in pieces in the ice cube tray and that way I can add some amounts to stir frys, or whatever.
For hard cheeses like cheddar and mozerella, I buy the bricks and not the grated packages. Then, I just grate it myself and freeze it or I just cut up the bricks and freeze them. When you unthaw the cheese brick, it crumbles on it's own ... so it does the job for you
Sometimes the baby carrots go on sale for 80 cents to a dollar, and I stock up on four or five bags at a time so I just throw the bags as is(they are prewashed) into the freezer and they cook up great. This can be done with most veggies .... straight from chopping to freezer bag with no fancy preserving needed.
Also, check out the dented cans that may be marked down. For most, there is nothing wrong with them and they do not affect the quality of the food. Also,
there is always a section of the produce section with expiring fruits and veggies. Sometimes you can get some great deals, as long as the stuff is still good, then run home and chop and freeze it.
I also freeze bread, then just take out the slices I need at the time and toast it. Whole wheat and grain breads don't last long otherwise, and I end up wasting most of the loaf if I don't freeze it.
Just remember .... most things can be healthy if we add veggies or fruit to them, and keep the portions in control. So, you can buy a loaf of 1$ whole wheat wonderbread instead of a gourmet 5$ loaf and as long as you combine it with the right foods ... you are still getting the benifit. I even add veggies to my Kraft Dinner! Then, it becomes a healthy and cheap meal.
Instead of buying Eggos, I buy the no name instant pancake mixes and make up half of the box or even the whole box, depending on the room in the freezer. To the batter I add things like chopped fruit, or mix in juice instead of water, and/or add wheat germ or bran or something like that. Then, I cook them up in the sizes I want and let them cool. I cut wax paper into squares and stack the pancakes, with the wax paper in between. Then, I put in tupperware containers and freeze them. Then, when I want one, I just pop them into the toaster to heat up. They work out great, and I get anwhere from 40 to 60 toaster sized pancakes .... for the same price I'd get 12 eggo ones that are toaster ready. I am not a baker/cooker, so believe me, it isn't alot of work