“…the average person treats a price ending in .99 as if it were 15 to 20 cents lower.”
The tendency is called left-digit bias, when the leftmost digit of a number disproportionately influences decision-making. In this case, even though the real difference is only a penny, research shows that, to the average person, $4.99 seems 15 to 20 cents cheaper than $5.00 – which results in selling 3 to 5 percent more units than at a price of $5.00"
Why Literally (Almost) Every Price Ends in 99 Cents
https://en.wikipedia.org/wiki/Psychological_pricing
EDIT: The left-digit bias is not just pennies / cents. It applies when going from $99 to $100…$399 to $400…$999 to $1000 etc.
EDIT 2: If you have a car for sale and you want $10,000 for it are you listing it for $10,000 or $9995?
Plenty of people are trying to deny that this effect exists or that it works. You can create a bunch of hypothetical one off straw man arguments where left-digit bias may or may not be the best solution or be irrelevant to the chain of events that make the sale happen. However, the act of pricing things at 99, 98, 95 etc. has been around for 140 years and has been studied by psychologists, marketers, and corporations.
All of the resistance to pricing things using left-digit bias present in this thread validates my post title. Merchants have been pricing that way for 140 years and yet when people sell their own items they don’t - and as this thread shows they don’t for a variety of reasons but none of those reasons makes the effect not real.
Why the hell is the post so controversial? Merchants do this, individual people do not. That’s it.
The problem isn’t the effect, the problem is you don’t seem to understand what it actually does. The idea is to reduce the price in such a way that a small discount appears larger, increase sales, and make the reduction back in volume. It works, and makes sense, and is done, if and only if you compete on price and trade in volume.
Your title is, at the time of writing: “People live their whole lives watching corporations end prices with 99 yet when they list their own items for sale they choose a whole round number and never question it.” This thread is full of people giving you reasons why they don’t or wouldn’t do that, meaning they clearly do question it, and are deciding against it.