Smartphone users looking to sell their current devices to pick up a new Verizon iPhone will find eBay a willing buyer.

The auction site yesterday launched a special two-week promotion through its Instant Sale feature that offers cash to people willing to sell their current smartphones.

Running through February 22, people can receive at least $200 from eBay by sending in any one of a number of phones, including an AT&'T iPhone 3GS, a Motorola Droid X, a Samsung Galaxy S Vibrant, or an HTC Evo 4G. Those willing to part with an AT&'T 32GB iPhone 4 can grab more than $500.

(Credit: eBay)

Prices vary based on the condition and functionality of the phone. But for a phone in excellent shape, eBay, of course, is touting its promotion as a better deal than people can get through Best Buy or Verizon Wireless, both of which are promoting their own trade-in or buyback programs to coincide with this week's debut of the Verizon iPhone.

eBay's trade-in values do appear to be more competitive, depending on the models and condition. For example, Verizon's trade-in plan appears willing to pay $212 for AT&'T's 16GB iPhone 4 and $285 for the 32GB version--as long as the phones function and the displays aren't cracked.

Best Buy's online trade-in option will pay $306 for the 16GB iPhone 4 and $337 for the 32GB model, both in the form of gift cards and with both models in good condition. Cash is available at lower amounts.

eBay upped the price to $405 for a working 16GB iPhone 4 in excellent condition and to $511 for the 32GB model. For models in good condition, eBay's offers are $344 for the 16GB model and $434 for the 32GB edition.

Verizon is also offering $200 in the form of a gift card for certain model smartphones. But that applies only to phones bought between through Verizon between November 26 and January 10 and requires the customer to buy a new iPhone at the full retail price.

To use eBay's Instant Sale for the smartphone promotion, you pick the smartphone you want to sell and indicate its condition. eBay in turn will reveal the price it's willing to pay. If you accept the offer, a free shipping label is generated for you to mail in your phone. After eBay receives and checks out the item, the money is put into your PayPal account.

eBay's Instant Sale tool was launched as a pilot project in October and will offer people cash for cell phones and other electronic gadgets.