Where can I purchase a pure-breed golden retriever?

I know I have to purchase a dog from internet by emailing with breeder. However, how can I purchase my money to the owner in order to get my dog (credit card? cash? check? etc.) ? If I pay my money online, is there any chance of getting scam by breeder? How can I get my dog home? Do they just mail my dog (if the breeder is out of my state) ?