What is the best way to ask someone whether their domain is for sale and how much they want for it? Where do you find out who is the owner?

no. fluther isn’t for sale.

on a more serious note – i go to this website to see the names of domain owners and how to contact them.

Try http://www.whois.net

whois always works for me, and a simple inquiry via email never hurt.

you should wrap a note asking your questions around a big bag of potato chips and send it to them. Developers love potato chips.

For example go to http://godaddy.com and type a domain name,will say already taken or available,if is taken click on(click here for info) and you will see all the information you want to know,phone number,email,etc