Use Mini Condiment Containers
I was getting in the habit of prepackaging my snacks in little plastic baggies, but that is incredibly wasteful, and the price adds up. When I decided to invest in Ziploc One-Press Seal Extra Small Square Containers ($6), it was a game changer for my meal prep. I preportion out servings of nuts or grapes and have them for the week. I also use them to portion out my salad dressings and other condiments so I don't have to worry about the entire jar of my favorite salad dressing being stolen out of the work fridge (not that anyone would do that!).