Well, the way we did it is to take offers, and 
then let other people who are offering on the 
cels know what the highest offer is. We had a set 
date for final offers.

If we only had one offer we considered it, and if 
it felt "right" we accepted it (usually based on 
if we could part with the cel, etc.). If it was 
too low we asked for the price that we felt was 
fair (compared to what we paid). If the person 
didn't want to up their offer to meet that price, 
we just kept the cel.

Hope that helps @_@

misa & casey 
(casey came up with the system, I just watched 
^_^;;)