Keep it as a spare. You may be very glad you did.
probably the route I'm going to go. According to Apple.com I would get $285 in credit for it. Another option would be Sprint stores, which offered $250. Fair price, but a $100 hit from a comparable sell on craigslist for a flawless 5 month old device with original 1 year AC left on it.
edit: it was $285 from Apple
edit 2: I guess my new question is whether they actually give you the same as what they say PowerOn will give you online. Again the device is literally flawless
iPhone 5 is going for $400-$500 on eBay.
Actually you can. First of all, you don't need "certified mail," that is mainly for flats (letters), you just need delivery confirmation (which is tracking & is free) and a signature for seller protection. Frankly, insurance is really a waste of money and will only help if the package is lost or damaged which is really quite rare and good luck on collecting on a claim in your lifetime. Using a flat rate padded envelope it is $5.25 shipping and $2.20 for a signature. I've been selling on eBay since 1999 and have sold well over 2000 items (many high priced) and only twice in 14 years have items been "lost" with one eventually being returned. I never take insurance, but of course that's up to the sender. Plus, if you get $400 insurance the signature is included anyway.
$40 to ship
plus money to ebay
plus paypal fees
plus the risk of loss
What I've found easiest--for me--is to use Gazelle.com and try to time my trade-in request as close to the release of the new phone as possible. I got $325 for my mint iPhone 5 and got in the door late. I probably could have gotten more if I'd registered a week or two earlier.
I realize that doesn't help you much now but I love Gazelle. It is so easy and smooth. I am probably leaving money on the table, however, so maybe next year I'll investigate eBay.
It's called a chargeback. I know a personal friend who lost money and their iPhone to a sale on eBay when buyer claimed that the phone didn't work. Money was taken from my friend's bank account immediately for the price the iPhone sold for and he never got the iPhone back. This was last year, he hasn't seen a dime of that money or his iPhone since.
I'll never sell a phone or anything expensive on eBay, I'd rather take my chances on Craigslist.
I sold my iPhone 5 for $511, it cost the BUYER $15 to have me ship it from CA to NY via USPS and it took 2 days to arrive, not $40 like you stated.
After all the fees, I deposited $510.69 to my debit account. I made a ~$40 profit on a phone I bought a year ago... I'm not complaining.