I have seen them for $99 at about 10" or so. But I can not stress enough FIND SOMEONE TO TAKE HIM BEFORE YOU BUY HIM. You do not want to be stuck with a 3' shark in a 6' long tank. What are your options?
1. Give him to a Zoo, do you realize how many people have already tried this method and a lot of zoos and public aquariums can’t even house a 6' shark for life
2. Release him back into the wild, this is the single stupidest thing you could do. First off I’m pretty sure they are a south east asian species and I doubt you in that region. Even if you were, if you ever housed any other fish that were not from the same region you could introduce brand new disease into that area and potently cause an epidemic.
3. Euthanasia, this is the only option for most people who buy a shark that they can’t find a home for. It is sad to see a perfectly healthy animal put down because of your impulsive shopping habits. Even if you could bring yourself to kill an animal that you have watched grow for years, you run into the problem of disposal of the carcass. I don't know of many garbage companies that will take a dead 3' shark off your curb.
Those are just some facts to look at before you purchase. Another good rule of thumb is that every LFS employ is out there to separate you from you money using whatever means necessary. I know this is a blanket statement but there are way too many con artists out there and it is just best to get advice from people that aren’t trying to sell you a $200 shark.