Check tropical reef in Rancho. He's got a good used one with a brand new pump you might be interested in. Can't remember the make/model. Give him a call and see if he still has it.
I have been told this is one area you don't want to skimp on and that I should get a protein skimmer rated for double my tank size which will be either a 150gal (60x24x25) or a 190gal (60x24x31). Looking for one that can handle 300 to 400 gallons and would like to say in the $600ish but cheaper is always better