First, I don't understand much of the Old School ebay goings on, in light of the current availability of boxes at the ToppsOnline store.
So in short: yeah, people are nuts.
I actually hadn't seen that Old School base sets were selling for $7 on Ebay.. but if that's true, I may actually purchase a few. Not for investment, but to have more to stick and to share with friends. I do dig the sketches, and I "value" them for myself and my collection, but I am far more excited about the base stickers.
Also, I wouldn't worry too much about current selling prices for base stickers. As Old School continues, and we (hopefully) get to Old School Series 6, 7, 8, etc... the "base set" of series one will become far more important than it seems now. Much in the way that "chase cards" lose a part of their appeal over time, I truly believe the base stickers in the Old School set will find their appeal increasing.
At somewhere under 8,000 base sticker sets printed, that's a pretty limited release. If "selling prices" is something you care about (and that's cool if you do) I predict that Old School base sticker sets are not going to be selling for $7 for long.