Slim pickings these days, but there is some good stuff that comes around. I'll be starting my search for another P10 in a few months. There's ways to crawl Craigslist, if you have a specific year/trim that your looking for. Cars.com is also a pretty decent place to search, but the majority of listings are with dealers.
Most of the stuff that you'll find around here is pretty well used and beat to crap.
Although some of the old timers who have been around have been letting go of their cars lately, so there is some clean stuff floating around.