Some investments that pay off:
Buy a small wedge of parmigiano-reggiano cheese. I have a 3-inch piece in my fridge that cost about $3.40. It seems really expensive, but a little goes a long way; once you taste it, you'll realize that stuff in the can really isn't all that - and it isn't really cheaper in the long run.
For cooking, use less-expensive extra virgin olive oil - Trader Joe's store brand is a good buy. But then, go get a small amount of some really, really good extra virgin olive oil. Whole Foods sells in bulk and lets you taste, so you can buy just 4-8 ounces if you want. Bones and Jones in Capitola will also let you taste, and Gold Leaf Spices in Oldtown Salinas does a killer olive oil tasting. This olive oil is for a special salad, for dipping bread as an appetizer, or for finishing some roast beets. You'll use only about a teaspoon per person each time and it makes a huge difference.
Sea salt. It's cheap and saltier than regular salt, so you will use less of it. But don't put it in the pasta water - that's where your kosher or iodized salt goes.
Fresh, local eggs. Flora's Farm at the Salinas Farmers' Market has excellent eggs; Star Market in Salinas carries some beautiful golden-yolk eggs from Chualar.
Real butter; unsalted lets you control the amount of salt in your dish. I don't use it every day, but a small amount on a cob of fresh corn is wayyyyy better than the chemical melange that is margarine. I like Clover Stornetta brand.
Garlic - before you use it, slice the clove in half. If there's anything green in there, pull or cut it out. It will make your garlic bitter, as will letting it get brown - if it browns beyond a light gold color, toss it and start over.
