This Spring I lost 6 goldfish to our resident Heron. That put me down from 22 fish to 16, so I started looking for a good source for more fish. I came across Toledo Goldfish on Amazon and looked them up. It's a huge operation out in Missouri. I think they are the retail/mail order division of Ozark Fisheries (next door), which wholesales across the country.
Here is a picture of their ponds from their website http://toledogoldfish.com . Shipping cost is included in their prices. A dozen fish were going to cost me $70, but the 2 dozen price was only $80. I couldn't resist the 2 dozen. I got 12 sarasa comets and 12 shubunkins. They were supposed to be 4-5 inches, but they looked more like 3-5 inches to me. After a 10% discount on my first order, it came to $3 per fish. My local garden pond store charges $7 each for the same types in the 3-5 inch size.
They were shipped by overnight FedEX and were double bagged in a Styrofoam cooler with an ice pack. They shipped a few extras and all 27 fish arrived alive. I lost one due to my failure to cover the drain in my QT and he got sucked in. Overall I'm very happy with the fish I got and would recommend Toledo as a good source for pond quality fish.
And here they are at home in my pond: