Can I trade a BlackBerry 9700 and a San Francisco phone for an iPhone 4s?

If there's any extra pay how much. They both have mild damage

Even if those phones where in top shape they not worth an iPhone 4S. The most maybe if your lucky is an iPhone 4 but since you said they were mildly damaged I say they are worth an iPhone 3GS. Still not a bad phone. Way better than what you have now