It means the person/company who owns the domain went on the website you're on (godaddy, name, etc) and is taking offers for it. You can contact the owner from the page where it tells you to list your offer price.

Yes, you can buy it if the other person is willing to sell you. You might need to pay much extra money for that domain. Use the service of Godaddy to buy that domain.

Check out http://www.Afternic.com/jijobose

yes you can but it may cost a lot

I want to buy this special domain name and I know it is not been use long time and some of the site says this domain name for sale and asking me to offer money. I am not sure how that works so please someone explain to me how can I buy already taken domain name or how to reach to person who has the domain name.