Use a vinegar solution to make your berries last longer
Prepare a mixture of one part vinegar (white or apple cider) and ten parts water. Swirl the berries around in the mixture, drain, rinse, and put them in the fridge. The solution is diluted enough that you won't taste the vinegar. Raspberries will last a week or more, and strawberries go almost two weeks without getting moldy and soft.