(Above, an example of the kind of parents' basement the 4G iPhone seller may be living in right now)
* First off, $5,000. That's all you could get for it? In your world, where you play nonstop with your XBox and live in your parents' basement, $5,000 is certainly a lot of money. It's just enough to help you buy that heavily used/modified 2002 Subaru WRX you've been lusting after for years (with a few grand tossed in by your parents) so you could drag-race with the dudes you meet every Friday night after drinking in Redwood City.
* Second, you gave up long-term revenue and positive publicity (as the guy who publicly returned Apple's lost 4G iPhone) for a short-term gain. Again, $5K is a lot of dough for someone still living in his parents' basement, but a) you have to pay taxes on it (unless maybe Gizmodo paid you in unmarked bills?) and b) you have to remain secretive about it out of fear of being criminally charged.
* Third, if you don't live in your parents' basement, you at least used to. Dweeb profile studies have shown that most men who read Engadget and Gizmodo have, at one point in their lives, lived extensively in their parents' basement. I should know. But that's beside the point.
Mind you, this is all just a theory on my part. What do you think? Vote in the poll below!