Hey Steve, I thought you were going to stay away from Koi? What do you consider inexpensive? The Frog Bog will have them for around $35. My mom has found them at Petsmart for $15 - 20 but I think they go fast because I have never seen nice koi at Petsmart.
Are you only interested in a yellow butterfly? I have some butterfly koi I need to find new homes for. A few babies from last year. I have one that is like a reddish brown that is really pretty and a couple of others that are dark coloring. Nothing too fancy. I do have a grey/black one that I would like to get rid of. I paid... well won't mention how much I paid back with he was a cute Utsuri (I think) but he lost all his red. A lot of koi loose the red in my pond for some reason. He is maybe close to 12" and he just doesn't tickle my fancy any more. I also have an all black butterfly koi if you are interested.
I have more goldfish/shubunkins this year that need to go if you are interested in them.
I'll ask my mom and sister see if they have any yellow butterflies. They both had some babies last year but I am not sure of the colors. My mom's though would only be 2-3". They were minnows when we brought them in for the winter.
Bonnie