This W502 Cobb in PSA 4 (with the paper loss on the front) recently sold in PWCC for $383 about 3 weeks ago:
http://www.ebay.com/itm/1928-W502-St...p2047675.l2557
The new owner has tried his hardest to shill bid it for more than this amount, listing it and removing it over the past week (along with the same card in PSA 3 which he also listed and removed three times in three days last week). Finally tonight he let it rip and shilled it all the way to $491 although I'm fairly certain the card was sold to a straw buyer:
http://www.ebay.com/itm/1928-W502-St...p2047675.l2557