How much is an iPhone 4s worth with a small crack?

I'm due for an update for my phone this Father's Day. I really want to get the 32 gig iphone 5s. With an update, it's about $299. I was wondering how much I would actually have to pay for the phone if I was to turn in my current phone (it's a year old, white iPhone 4S with a small crack at the bottom of the screen) for money.

If you trade it in for credit, you will most likely get an insignificant amount of money for it.

Try listing it on craigslist for a price you find reasonable and you could probably get more money from that.

This for trade in. Iphones always hold their value well. (Cracked would deduct some of course)
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Apple also recently boosted the trade-in values for the iPhone 4 and the iPhone 4S. Apple Stores now offer up to $99 toward a new device for an iPhone 4 and up to $199 for an iPhone 4S.