People list things for excessive pricese for several reasons. In my opinion, here are some of them.
1. They don't really want to sell it, but if they got a "huge" amount of money, they'll be willing to sell it.
2. They don't actually have the item, and instead of taking down the listing (they might have originally made the listing with multiple items, but are now sold out and waiting for more), they just put in a price that they feel is too high for anyone to bid on it or buy it. And if they're wrong, the price will be high enough so either cancel the sale without angering the buyer too much or bend over backwards to find the item quickly and sell it.
3. Something illegal or improper is taking place, like shilling bidding or money laundering.
4. The person is basing their selling price not on what it's worth, but what they paid for it. Many sellers feel that what they should sell an item for is based on what they paid for it. This makes sense if they're in the business of flipping, but if they're just trying to get rid of items, I find it annoying. Usually this is present with buyers who don't really know the market for an item they're selling because they buy into marketing hype.
5. They know the listed price is way too high, but they're hoping there's at least one sucker out here.
6. They're not sure how much the item is actually worth and aren't in a rush to sell it. So they put an extra high price and figure they'll take a "wait and see" approach to the sale.
