I also agree that having a "number" in there isn't that good an idea.
I think the important things to focus on with a domain are that when you say it, people don't ask you to repeat it or spell it, that you can easily say it on a radio advertisement and people will be able to remember what it was to type it in when they get home and that there are no other words in it so that when it's read, they definitely say your company name in their mind (ExpertSexChange.com anyone?) I think it needs to say something about your product - but not necessarily everything.
Here's my next burst:
stuffsoldonline.com
youpackwesell.com (possibly reads as you pack weasal? :)
for that matter ... packweasel.com - although weasel has a bad connotations ...
sellchimp.com
sellmyelephant.com
sellmygorilla.com
(I like animal ones because the logo draws itself and they're fun by default!)
packsellpay.com (this is obviously a direct description of the transaction)
yougotthestuff.com
packagerider.com
packedintight.com
packedandsold.com (this doesn't read particularly well)
actually i would just like to note there that in terms of being easy to read, say and spell packadoodle.com should really get another look-in.
takethissellthis.com
takeandsellthis.com
takesellpay.com
annnd i'm spent.