put the mac pro on auction at ebay not buy it now.
seller fees are lower for large auctions on ebay then buy it now.
a 10 day listing on ebay for $1999 starting auction is $2.40 max auction fee is 50 bucks
if you have a better mac pro then a base list it just under what you want. say a hex core is 3600 new and you would like 2900 for yours. list the pro at 2700 it is 2 bucks to list it!
pulled from these two links
http://pages.ebay.com/help/sell/fees.html#fvf_auction
http://pages.ebay.com/help/sell/fees.html#if_auction
Final value fees for auction-style format listings
Auction-style format listings
Final sale price
Final value fee
Item not sold
No fee
$0.01 - $50.00
9.0% of sale price (maximum charge $50.00)
$50.01 - $1,000.00
$1,000.01 or more
To learn more and see an example
so ebay will cost you under 60 for a 2000 dollar sale
paypal will cost 50 bucks on a 2000 dollar sale.
another good place to list is
http://www.audiogon.com
list is 6 bucks and 1 or 2 percent. limit shipping to whatever please you. list is 30 days. audiogon is for hi end audio but you can push your machine itunes server ability to get it listed. I sell on both sites quite a bit. I use the same name as this site. feel free to ask me for free advice on listing safely.
phil