chill with the hate, bro.  If you don't want to buy his stuff, don't comment on it.  The truth is this: you want to seem cool to a lot of other kids on the internet by trying to show that you can find some deal cheaper, or that you sell stuff for cheap, or that you are just a jerk who is trying to ruin someone's thread.  I don't think $300 is unreasonable at all considering you can't find those sizes any more and considering the jacket is brand new (retails for $235 and it is rare currently) and the pants are in good shape (went for $180 and are currently hard to find as well).  So, it seems like you didn't pick up on the message in elementary school: if you don't have anything nice to add, sit there at your own computer and be rude to yourself.