Many people throw out vegetables that, while they aren't rotten, just don't look appetizing. Consider this: So much food waste comes of doing that! And it's money down the drain, along with nutrition.
Raw tomatoes: Raw tomatoes that have wrinkled skin and which are a bit soft can either be turned into stewed tomatoes with a little water and a saucepan, or into tomato puree or sauce in a food processor. Don't use them if they have black spots or mold, but otherwise, go for it!
Eggplant: Cook it down to puree and make baba ganoush, a dip for bread, tortilla chips or crackers.
Berries: Make jam with them. Even refrigerator jam. All you need is a saucepan, some lemon juice, maybe pectin, and some sugar/sweetener and voila! You have something to spread on your toast.
You can freeze carrots, collards, spinach, celery and other items that will be cooked down anyway, even if they are slightly soft, as long as they don't display any slimy texture. They can be used in soups and stews, curries or stir fries later on down the line.
Oranges and lemons/limes: can be juiced. The juice can be frozen to extend life. Also, you can make preserved lemon, either sugared (for a treat) or salted (as a condiment).
Peppers: can be placed in vinegar to extend life. The flavored vinegar of a spicy pepper can be used to season dishes. Just add more vinegar.
Try some or all of these and let me know how they work out!~