How much 4S iPhone cost if used, unlucked and in a good condition?

A close friend is offering it to me for $250.
Is it a good deal?

Haha. Considering you can buy an unlocked one from version for 1$.

On bestbuy.com to purchase an unlocked phone (AT&T) 16 MB 4S would cost you $599.99. So you're not getting a horrible deal. And Verizon's $1 4S would require you have a 2 year contract. You can look around just like I did but it's not a bad offer.