I'm not as experienced as many of the other folks on here but I have hundreds of these 1c Washingtons from when I was a teenager all wrapped up into bundles of 100. As was mentioned, they're extremely common.
You're going to see all kinds of things on
ebay and I think sometimes people just put things up there with outrageous prices to see if someone will bite. I don't think those links you posted were actual sales, they were auctions that ended without a buyer and were re-listed. So the seller just keeps reposting the same thing trying to get a buyer.
The suggestion to check out retail prices from a catalog or a website from a place like Mystic is a good one. That will get you in the ballpark. But you won't be able to charge that price on
ebay if you want to actually move the item.
Good luck!