let's use your example, $1000 for an iron rod. it would seem overpriced (i, personally, would not pay that and would go iron mining myself), but consider its use: iron rods are used for crafting, to build forts and, if you are doing or planning to do charlie quest, you need a lot of iron rods (used to be 100 of them, now 50).
from that point of view, someone listing 10 iron rods for $10,000 may tempt a lot of potential buyers. it is overpriced, but also means that the buyer will free some time to get the other products they need (granite, wood, leather, cotton, coal, hammers are needed to craft ONE bayonet; to build a large fort, you need to get insane amounts of products, including 2,100 rolls of cloths and 1,575 hammers; and for a quest like charlie, you need 5 sledgehammers, 50 nails, 50 iron rods and 100 wood to advance to the next step). so, when you look at it from that perspective and you have the money, sometimes you feel stupid but you end up paying the stupid prices.