Mine were 29 cents each at Petsmart. I got 10 feeder goldfish 4 years ago, and still have 9 of them, plus they've produced a few new ones that have survived. Biggest one is over 6in. long now, and looks just like a koi to me. Plus they're easy care - all they want is enough water to swim in!
I definitely think those wily heron know when you've spent a lot on a fish.
