I saw a copy at EB Games last week...used for $40...asked them if they had any sealed copies because it's only $20 new. They didn't.
$30 is actually a little cheaper than the average Ebay price...and if you find this in-store it's probably a new copy that they opened to sell as used. I may use my trade-in credit to grab one of these next time I see it.
1up ran an interesting article recently entitled "Are Those 'Rare' Games Really Worth the Money?" in which it details the case of Gitaroo Man. Apparently there's some company called GameQuestDirect that's been reprinting Gitaroo Man so its price has been dropping like crazy nowadays since they're flooding the used bins at Gamestop.