If your account is banned, then what about the sites? Are they banned from displaying adsense as well if you want to sell them and would this decrease a site's price? Or is the ban on account and not on the sites?
depends on the reason of the ban,but generally they don't ban your sites unless there is reason to. you can always check to see if they're banned.
As far as I know Google banned only account and website. If you bought you a website and put AdSense from you AdSense account it should be OK. May be it will raise a flag and they will check manually but you could never know if the person that sold you his site was banned.
Ok thanks - I was just reading in some topics that some people who bought banned sites had to wait like 6 months?