Trader Joes Fancy Berry Medley; Frozen berries are much cheaper than regular berries and won't go bad in the fridge! This blend is my favorite (blackberries, blueberries, and raspberries). Berries are a great source of fiber! I like to have them post-workout since they're also a good source of fast digesting carbohydrates. Other frozen berry blends are fine as well, just find the right one for you!