Availability is also a big factor. While it may cost me 25 to get a Temmincki here, you could not get it unless you took a long trip to get here, or you had it shipped. Either way its going to cost more than the value. The best way to find great plecos, is to talk to a LFS that you trust, and look at their ordering lists. They should have several plecos on the lists. If you have the datz, or the Aqualog book, take it along and look them up if you aren't certain what they look like. One of the LFS brings in lots of Plecos, and I window shop all the time. 80% of them come home with me but that is cause I hoard them. I even look at LFS I don't trust because they can order from a good company.