There are several of these out there, and they tend to sell for roughly the same price, same with most 28-80s by third parties, 135mm 2.8s, etc. etc. They just tend to run about the same price. One particular one I'm looking at is on keh, a Sigma APO 70-210 2.8 for Canon EOS. EX condition for $275.00. AF might be kinda slow, but maybe a Nikon mount lens, w/ in-body focusing might make a difference or if it doesn't you can prefocus and anticipate the focus to some amount. Even if its focus is not so hot, is an older 70-210 2.8 a possibility for a cheap, constant 2.8, beginner's sports lens?