Here are some simple guidelines for this topic. You shouldn't forgot these information to post here.
1. URL of the website or domain
2. Stats if there are some showing history of traffic
3. Tell us how much revenue it generates and if you can than prove it
4. What is the PR or placement in SE
5. What is content of the website
6. Where visitors usualy comes from
7. Finaly the price you are asking as minimum
Hope it makes selling or buying easier.
