Limit orders set the highest or lowest price you're willing to buy or sell at. However, there's a possibility that your limit order may be filled instantly at the current market price, resulting in the payment of a taker fee instead of a maker fee.
For a long/buy order, if the order price is equal or greater than the best ask price, the order will be filled immediately. The executed price will be the best ask price.
For a short/sell order, if the order price is equal to or lower than the best bid price, the order will be filled immediately. The executed price will be the best bid price.
For more information, please refer to the examples provided at How do Limit Orders Fill?
