Both NextWorth and Gazelle say they will pay up to $100 for the iPhone 3G models and $200 for 3GS models, if the devices are in good condition.

also offers $100 for the 3G and $200 for the 3GS, but for in-store credit or gift card only. It sends the devices out to be wiped, and provides free shipping if you work through the Web site. Radio Shack will not accept devices with cracked screens, scratches, or water damage; the phone must be functional and disconnected from service. The company will accept phones without the battery and charger, but pays a little less for these devices.

provides an online quote for iPhone 2Gs and 3Gs. For example, it says it would pay $120 for that 16GB iPhone 3G. Shipping is free plus insurance and packaging, and the site advertises that it will buy your device in any condition, even if it's broken or missing the battery and charger. Cash for iPhones advertises that it will wipe the device clean, and pay cash in one business day.

quoted $85 for our old 16GB iPhone 3G. However, the service noted that the suggested price was based on visual inspection and could change if they were not satisfied with the device I sent in. After the online form asked for my e-mail address, phone number, and address, it forced me to "accept" a terms and conditions contract that states once they receive my phone, it cannot be mailed back, which means if they decide it's only worth $10, I have no recourse to change my mind. They do provide a shipping label for free shipping, but I wouldn't use this service even if it was the only one available.

had the same form as Eco New, and when I entered the same information for an iPhone 3G, it offered $148. Again, however, I was forced to "accept" a terms and conditions contract. It asked me to select the method of payment I prefer, from the single option of a prepaid Visa. Why ask, if there is only one option? And, once again, I had to enter my contact information before it would reveal the shipping arrangements, which are the same as those of Eco New. MyBoneYard offered a postage paid label that you can print and attach to the package.