if you're really concerned about the quality (from an age, health, genetics standpoint), on aquabid.com you can generally find nice pet quality fish for 5-10 dollars with another 5-10 dollars for shipping. 10-20 dollars for a good quality fish.
it's like the difference between getting a puppy from a respectable breeder, and going to the pet store in the mall that sells puppymill dogs. You'd love either puppy just the same, and you're spending a little more, but better to support the person working to improve the breed than to support the person destroying the breed for money.