TF2 trader Shadow brings up a good point, store prices vs. TF2 trading prices:
"Dude there's a mistake there infernal impaler (clean) should be 7-8 refined and the dirty one 4-6 just like the aspector they are the same price on the store."
Sometimes when an item first enters the marketplace it is close to its store price (or if its a promo from a game, its game price). However, this is NOT always the case. Moreover, two items from the same promo or the same price at the store can have completely different demand on them.
Case in point as Shadow brings up the Infernal Impaler and the Apparitions Aspect. For whatever reason people seem to place more DEMAND on the Aspect. Therefore a higher price can be asked for it. It's not complicated but a lot of traders have trouble with this and sometimes its hard to rationalize.