I sell cameras and lenses all the time on ebay, I get enough more of a price to pay their fee. $3500 for 250K camera seems a little high, I just bought one for $3600 and it had 1400 actuations, another person had one for $3700 with under 500 actuations.
I see some high usage cameras on Fred Miranda that are not selling for $3250. Ebay charged me $65 for selling a 1700 lens a couple of weeks ago, thats 3.8 % not 9%.
How do you know your $3600 camera had 1400 actuactions? Nobody knows except for Canon... If I were a bad person I can sell mine on ebay and claim it has 50K actuations... Nobody will ever know. That's why I don't buy used. Unless there is an authentic Canon Service report with the REAL number of actuations, people will either lie or, like me, not be sure of how many photos I've done... I assume around 250K averaging my daily usage...
I use eoscount, it is the only windows based software that will read the actuation count from a 7D or a 1D MK IV accurately. Does not work for a Mac, unfortunately.
Many people now use it since it came out 3 or 4 months ago. I was a bit dubvious, but I've used it on cameras where I knew the count, and its right on. On my 5D MK II, It returns the same count as astrojargon eos info. I've taken a few images since I bought the 1D MK IV in May, so its now up to 2800.
Unfortunately, it still only works on a limited range of cameras, but the 1D MK IV is one of them. If you have a windows pc, try it and let us know what you read. http://eoscount.com/