My cooking "trick" is that I have my recipes collected by the core ingredients involved - for instance, recipes built around beans are grouped together, or around say root vegetables. That way, I can buy a large amount of that item when it is on sale, and only a few supplementary items to put together a meal plan for a week.
This week was a bean week. So yesterday I bought 2 lbs of dried pinto beans, 1 lbs of dried kidney beans and 1 lbs of dried white beans. I soaked them all day yesterday, and now they are cooking in my three pot crockpot.
When I get home, I'll start on today's recipe - 5 bean salad. It includes canned green beans and wax beans along with the three beans listed, as well as shredded cabbage and a few herbs, vinegar and sugar. After dinner, I'll take about a third of the remaining pinto beans and make refried beans. Tomorrow we'll have tacos (using beans, rice, shredded cabbage, salsa and cheese). Then the next day I'm making a bean curry in a loosely indian style using some of the herbs from the salad and a can of coconut milk. Served over rice (left over from taco night).
You get the idea
It saves both in money and cooking time. And it is quite possible to keep it interesting this way. I often will do the same thing with items that are hard to buy in small quantities - like kale or cilantro.
