Am i being scammed or am i just a paranoid first time ebay seller?

I'm new to eBay, and I originally made my account to buy a few things but now that money is tight right now I decided to sell. I posted a listing for a iPhone 4S with bad ESN, please know that it's not stolen like people think bad ESN phones are, I simply couldn't pay the bill and I stated that in the listing. Within FOUR minutes of posting the listing someone bought the phone, for $200 plus $4.95 shipping. I read some fourms on ebays site about people buying iPhones, paying for them, then claim they did not receive it and open up a claim to get a refund or they will take stuff out the phone then make up a lie to get a refund. The buyer has good feedback, and I decided to see what he bought from those people, to my surprise he bought all iPhones (all 16 feedbacks were from people he bought iPhones from) I don't understand why someone would want all these iPhones, he bought all of them within 30 days. His account address is to a suite in auracom tech inc in brooklyn NY. After reading all the fourms about the scammers I'm kind of nervous. Can someone give me advice? He just officially paid for the item 20 minutes ago but i can't get the money until 3 days after it has arrived to him so I don't have long before I have to head up to the post office and mail it. Do you think its a scammer or not? It surprised me someone bought it within 4 minutes of posting it, and the fact it sold for $200 with a bad ESN - $200 can buy a new iPhone with a contract and clean ESN so that's why I'm surprised

If he has good feedback and PayPal already confirmed that the payment was made, then don't worry. Just make sure when you ship the phone, you ship it with a method that includes tracking and delivery confirmation.

As far as why he bought a bunch of iPhones, to me that doesn't seem scammy, it just means he needs a lot of iPhones for some reason - maybe he fixes them?

And buying for $200 also isn't surprising, yes you are right that you can get a new iPhone with a contract for $200, but the contract being included really means that new iPhone really costs Way more than $200.No-contract iPhones cost LOTS more than $200.

If his feedback is good than I wouldn't worry… But it seems to like he's got some kind of company going on over there…

Probably most ppl on emay are scammers.
never ship until cash is in your bank account.
sell it on craigslist, no fees and you get cash.

Sounds a bit strange to me. But if he has a good track record then you probably don't have anything to worry about. For Future Ref. Here is a free listing to sell something on a very good marketplace site.
http://www.tripleclicks.com/11788231/go