Kind of hard to say. I last time I saw a price on one was about 3 years ago at a cheap Fish store. They wanted $11.99 for it( at 3 inches). So, I would have to say a normal fish store would ask between $20-$30. Most plecos over 50cm don't get much as no one wants them. And lastly factor in that we are in different countries, so I don't know the demand there.
Ok I get it ,just wanted your opinion ,I thought it was a fair price since I don't see them too often around here ( or any nice looking pleco ).
I still get happier by every time I look at him