All content goes with it? It'll depend on the content and nature of the site I guess. For me, I'd not be interested in a site that is about Nascar Tires, but I might take it if it was about Toe Nail Polish (more women buy online than men). Other factors such as the number of links coming to the site, the type of sites linking, if the site has ever done any banner advertising, adsense, clickbank - if it's been banned from any of them too. Age of the domain will play a factor too.
The site is worth what you can get for it. You might want to visit Flippa and see what they'll offer. A PR4 is not the determining factor on price. It's handy to have Page Rank numbers when looking to sell advertising, but that's from years ago now. True marketers don't look at PR much any more - it's all about content and the value of links.
One person might offer X while another offers Y, it depends what the buyer wants the site for. It's just like any other collectible out there that you are selling, to the right person it could be worth more than even you (or we) think.
Please your clients & thank them from time to time.......they are just like groupies that keep the band going strong.
What is the revenue of the site. Usually the price is the revenue/month*12.
I don't monetize the website that much yet. I just put some Adsense ad units and posted reviews on affiliate products on the website. Thanks for the info though, I didn't know that it's the way of setting the price.