I bought the HOB turbofloter for <$60 on eBay. They have been around for awhile so they are pretty easy to find used. I have it on a 72 in my bedroom and the one nice thing about it is that it is silent with a muffler on the air hose.
As far as performance I can't really say. I only have two small fish in my tank and all I ever get is a light green tea colored skimate that smells more salty than anything. I don't know if it is under performing or just too light of a bioload. It does fill the chamber pretty full of bubbles, and it does produce skimate all day though. Another thing I am not a big fan of is its conical skimmer neck. The top opening is about the size of a quarter and I have to clean it about every other day, a quick swipe with a old toothbrush, to keep it working best. I have no sump on this tank other wise I would have definitely gone with an ASM or other needle-wheel skimmer.