2 cups chopped cooked green beans (or 1 tin green beans)
2 cups chopped cooked yellow beans (or 1 tin yellow beans)
1 can red kidney beans
1/4  cup vinegar
1/4  cup vegetable oil
1/3 cup sugar
Salt and pepper to taste
1 tsp parsley flakes
1 onion, thinly sliced

Mix together and let sit overnight, then enjoy the next day!