There are also phone apps you can run that watch craigslist and alert on keywords.
Last summer there was a 500 with hdd (but it was listed at $500), then a 1000 but it was at a local retro game store on the other side of the city so I never made it down there, then the 2000 that I got.
There were two more 2000's this summer, one has dropped off now and the remaining is $250.
Thats just in my city.
Amazon also has used resellers too.