The story on the screen fault was that a drop caused corrupt images on the screen, the was it was written made me think they actually already knew a new screen wouldn't fix it - I can just imagine it being relisted again with a "A clever buyer can probably fix this with a cheap screen but I don't have the skill" kind of message in a week.
I got my Iphone 4 cheap on a plan and my replacement 32gb iphone 5 two years later for free on a plan, I gave my wife my iphone 4 but if I'd sold that for $450 second hand I only paid $250 or $300. Two years from now I can sell my free Iphone 5 for another $450 or more when I resign for a free Iphone 5s / 6 / 7.
I cannot believe how these things keep their value although I have to say, until I broke my wifes iphone 4 changing batteries too many times (buying crap aftermarket batteries on trademe that had less life than the 30 month old factory one) it still worked as well as the day I got it.
You can buy an original Samsung Galaxy S i9000 *BRAND NEW* on Trademe for $295 and thats Samsungs closest competitor releases within a month or two of the Iphone 4. Not to mention the Samsung with languish on Android 2.3 (keeping it official) and the Iphone 4 still runs the latest release iOS.