How to read DonutSMP prices
What the cheapest price, usual price and best buy order each mean, and which to trust.

The three prices on every item
The cheapest price is the lowest listing on the auction house right now, per single item. It's what you pay if you buy this minute, as long as nobody beats you to it.
The usual price is the median listing. Half of what's listed costs less, half costs more, and jokes priced far above the rest are left out. Use it to judge whether the cheapest price is a bargain.
The best buy order is the most anyone is offering on /orders. It's what you get if you want to sell right now without waiting for a buyer.

A stack and a single aren't the same price
Everything is shown per item, so a stack of 64 for $64K reads as $1K each. A seller often charges more per item for a single than for a full stack, so the cheapest price each may not be available in the amount you want. Check the amount column under Cheapest listings.
Check how many are listed
With hundreds of listings, one seller can't move the price far. With three, one sale can double it. On a thin item, read the price as a rough guide and look at its chart before you trust it.
Reading the chart
The line is the cheapest listing each hour. When the last normal copy goes, the only thing left may be a troll listing, so hours far out of line with the days around them are smoothed over, unless listings at that price were really going. A move that lasts stays on the chart.
The bars underneath count listings that left with time still on them. Most were bought, but a seller taking theirs back looks exactly the same, so we call them gone rather than sold.
New to the auction house?
This short video walks through how the auction house works on DonutSMP.
