Also, if you used the phone for Sprint it has to be used for Sprint by whoever wins it. You are able to have phones flashed over to other carriers but the down-side of that is that the phone may not work properly.
If it's a sprint phone it has to be unlocked to be used on another carrier, you can't just put any sim card in it and expect it to work or it may not even need a sim card. These things should be known.
This phone doesn't have a SIM card... I understand there may be a small expense for connecting it to a carrier other than Sprint... but really... cmon' the phone is free.
I completely understand the phone is FREE but these are the questions that people will ask, believe me I've had my share of questions and comments from bidders. Good Luck with your auction!