The Binance exchange provides a discount if you pay a fee for trading with its own tokens.
To do this, you must activate the corresponding function in your personal account on the exchange and have a certain amount of BNB in your account.
You can do this on the page: www.binance.com/en/my/dashboard. In the «Your Trading Fee Level» block, you need to activate the «Using BNB Deduction (25% discount)» checkbox.
Next, you should regularly monitor your BNB balance so that it is always enough to pay the commission.