Spread measures disagreement
The bid-ask spread is the gap between the highest visible buy order and the lowest visible sell order. Narrow spreads often indicate an active market. Wide spreads can indicate low activity, uncertainty, manipulation risk or simply a specialized item with few participants.
Depth measures executable volume
Depth is the quantity available across nearby price levels. If your stack is larger than the best order, execution spills into worse prices. That is why quantity-aware Immediate pricing can differ sharply from Top Buy or Top Sell.
Why expensive items need more caution
A rare module, blueprint-related item or specialized hull may have very few orders. One unusual order can move the visible midpoint dramatically. For high-value decisions, inspect the book and recent history rather than trusting the first number.
What a wide-spread warning means
A warning is not a prediction that a price is wrong. It is a signal that the market deserves more investigation. Check other hubs, change quantity, compare recent observations and consider whether you are willing to wait for a limit order.
Practical workflow
Use Market Search to inspect the item, then use Price Checker to see how that item affects the total value of a larger inventory basket.