What the invisible cost really is
• The market has no 'single price' — there is always a gap (the spread) between the bid to buy and the ask to sell
• Slippage is the difference between the order price and the actual fill price when an order is filled across that gap
Why it widens
• The thinner the liquidity, the wider the gap between quotes, and a market order consumes that whole gap instantly
• That is why costs grow in low-volume altcoins and during sudden swings
Where people slip
• They count only fees as cost and ignore the spread and slippage that pile up on every trade
The real cost is not the fee but the gap between quotes. Market orders are for urgency only; limit orders in ordinary times avoid crossing the gap.
In your recent trades, did you count spread and slippage costs, not just fees?