That's eBay, people are always paying silly prices there.
Remember that many people are addicted to shopping and they get a sense of achievement from "winning" an auction.
They often don't know the retail price of what they're buying, sometimes don't even know what they're buying, and/or get swept away in the competition to "win" and loose track of the value of what they're bidding on.
Auction houses survive because of that, if people were always sensible in their bids most auctions wouldn't sell anything because the buyers would deal directly with the sellers rather than compete with each other.

Remember that many people are addicted to shopping and they get a sense of achievement from "winning" an auction.

Good point i never really thought about that before tbh..