are you auctioning the jailbreak method? or are you auctioning a jail broken iphone? did you know that jailbreaking a contract phone is illegal now and has high penalties and fines and also renders a persons phone to be useless. the carreir will not honor any warantees or insurance claims of the phone is jailbroke, I would not personally recommend this to anyone for their own good. im not trying to make your auction look bad, but people need to be aware of what they are actually getting themselves into with this type of auction. some jail breaks are irreversible and some may damage the phones software and render it useless as well. If the carrier detects that the phone is jail broke, they can flash your phone and that will be the end of that. I work for a radioshack as a manager and i have had that happen to customers.
Apple suggests that doing that to your iOS device may lead to security vulnerabilities, instability, shortened battery life, unreliable voice and data, disruption of voice and data, disruption of services, inability to apply future software updates; it may result in Apple denying service for your device.
Apple dont want jailbreak brcause you get everything for free so they can get money out of you! Many people who DONT know how to use a jailbroken iphone get into trouble because of it.. So there is nothing wrong with jailbreaking as long as you know what youre doing!