Why can the price you see for $ETH differ from the price an order fills?

An order book shows buyers’ bids and sellers’ asks. Their gap is the spread. A market order takes available offers; if the order is larger than the quantity at the best price, it may fill across several levels. That difference from the expected price is slippage.

A limit order sets the worst price you will accept, but it may remain unfilled. Before placing an order, look at spread and depth as well as the headline price. Speed and price control involve different trade-offs.

Source: Binance Academy, “What Is Liquidity and Why Does It Matter?” #CryptoEducation