Even lettuce is cheaper purchased "raw". We can get romaine lettuce at $0.99/lb, or pay $2.99/12oz of prepped romaine. Grapes, the boys LOVE them, but I try to only buy them at $0.99/lb. Bananas suck too, and they never go on sale. $0.42/lb is the usual around here. Baby spinach is more expensive, at about $3.99/12oz bag. I have seeds for lettuce and spinach, just need to get some free compost (for cost of gas) and I think I might try growing it in one of those under the bed storage containers and around the house. The spinach should do ok in that tub, since I plan to harvest at a very young stage. Plus if I toss some spinach outside and just let it go, I can hopefully collect seed so that I don't have to pay the $1.19 for the seed packet next year. I also like doing berry harvests. Our neighbors at my mom's place let us pick blackberries. In two hours, I can collect at least a gallon size bag of fresh blackberries, which makes 6-7qts of jelly. By purchasing dutch gel in bulk, and sugar in bulk (I have to go get another 50lb bag of raw sugar at $35), I can really cut costs and still have a somewhat healthy product. Well, healthier than what you buy in the store anyways... Lotta sugar so it's more of a treat than a health food, IMO. I also make thinner jelly (first time was pure accident) to use as a sauce... I LOVE thin blackberry "jelly" in cottage cheese.
Another thing, when buying bulk, never purchase more than you can use in the time before it expires... Otherwise this is just wasted food and wasted money. Once I get the birds going again, they'll be my garbage disposals. I HATE scraping small amounts of food into the garbage, but when I had birds, it always went to them, so I didn't feel like it was as much of a waste. I am not the kind of person to put half eaten food back into the pot. It's one thing to save half a plate and put it in the fridge for that person to finish later, but I don't like the idea of transfering germs between people (even if they are family members, you can still spread illness).