iPhone trade-ins: The best deals online

By next week, we expect to be introduced to the new iPhone, and shortly thereafter Apple's latest smartphone will be in the hands of consumers everywhere. Many Apple addicts will inevitably begin to neglect their older model iPhones once they've gotten new ones, letting their old iPhone gradually lose resale value in a drawer or on a shelf somewhere.

Apple recently decided to go after some of those scorned old iPhones, offering to take them back as trade-ins in exchange for Apple gift cards through its "recycling and reuse" program. But the field of online outlets looking to pay good money for old iPhones is crowded, and sending your old iDevice back to Cupertino is far from the only option. It's now possible, for example, to accept an offer for your old iPhone online from Walmart and instantly get a credit at the mega-retailer that you can spend even before sending in your used device.

Here's a brief breakdown of some of the prices being offered online as of Thursday for those older iPhones that will instantly become a little less cool and desirable next week:

Apple: Available online and at Apple stores, the company will take back iPhones, iPads, and Macs in exchange for Apple gift cards.
Price for a used iPhone 5 in good condition: $296 - $406
Price for a used iPhone 4S in good condition: $181 - $241

Walmart: Walmart offers store credit that can be spent at its stores or online instantly (following a credit check) after accepting an offer for an old iPhone. Walmart offers the same deal for all sorts of old consumer electronics.
Price for a used iPhone 5 in good condition: $250 - $350
Price for a used iPhone 4S in good condition: $153 - $225

Best Buy: Best Buy's buy-back program is similar to Apple's in that it offers gift cards in exchange for old devices accepted online or in-store, and it offers free recycling for gadgets determined to have no value. The retail chain previously offered a "deal" to iPhone 4 and 4S owners, encouraging them to trade their phones in for a new iPhone 5, in a clear move to try and deplete inventory before the new iPhone is likely revealed next week.
Price for a used iPhone 5 in good condition: $300 - $400
Price for a used iPhone 4S in good condition: $170 - $230

Gazelle: Gazelle doesn't offer the highest prices around, but it does have an easy and leisurely experience, allowing users to lock in their price now, but not have to send in their old phone right away. That means you can get an offer on a used iPhone and accept it today, but you can take up to 30 days to actually get the device to Gazelle. The clear advantage of this is the ability to wait until you have that new iPhone in your hands before sending in the old one -- nothing worse than iOS downtime.
Price for a used iPhone 5 in good condition: $200 - $320
Price for a used iPhone 4S in good condition: $130 - $190

Nextworth: Perhaps the least known on this list, Nextworth might offer the best of all worlds, with some of the highest offer prices, free shipping, a 30-day guarantee for quotes like Gazelle, and a partnership with over 1,500 retail partners that allows you to sell your old iPhone in-store. Nextworth also gives you the choice of getting paid via cash, PayPal, or gift cards.
Price for a used iPhone 5 in good condition: $240 - $410
Price for a used iPhone 4S in good condition: $165 - $245

eBay: It takes a little more time and effort, but the folks at eBay swear to me that the online marketplace is the best place to swap an old iPhone for cash. The company claims that used 16GB iPhone 5 models on eBay currently have an average selling price of $450.
Price for a used iPhone 5 in good condition: as high as $591 and above
Price for a used iPhone 4S in good condition: a 16GB AT&T model averages $307

iCracked: Selling your old iPhone is great, but to get top dollar you'll need to have kept yours in pristine condition. Judging by the number of cracked iPhone screens we've all seen our friends toting around, that's easier said than done. Enter iCracked, which is setup to not only help you repair your cracked or otherwise abused iPhone, they're also much more willing than the above places to give decent cash for damaged devices. For example, a cracked iPhone 4S could still be worth $125 -- not bad. In addition, they also offer comparable prices for iPhones in good condition to the other outlets above.