I found this chart that lists how much fiber different types of fruit contain: www.fitsugar.com/Fiber-Fruits-209893
It looks like a cup of blackberries has the most, with 7.6 grams of fiber. Who knew?! Buying frozen can be less expensive than buying fresh, and it's easy to mix it into a shake or put it into some yogurt. I personally like apples - they're easy to tote around and I keep a bowl of them in my office at work so I'm not tempted to grab the goodies in the kitchen.