It's not hard to beat that price. You just need to know the right "Unlock Suppliers"

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You could factory unlock Sprint iPhones about a year ago. Since then, Sprint has changed their unlocking policies. But, you can still factory unlock the Verizon iPhone 4s. Both networks have gsm capabilities in their iPhones. The downside is, they only work internationally. But it's still a good idea to unlock them and sell them overseas.
As far as the newer devices for Verizon (for anyone that doesn't know) they all come factory unlocked.