ECN fees are unique to each brokerage firm. Each firm has its own deal negotiated with select electronic communications networks. The best way to find the lowest ECN fees is to compare the different brokerages. An ECN fee of $0.0008 to $0.0035 is not unreasonable. All brokerages either charge the user the ECN fee or decide to absorb the cost to attract more users, but the fee is always present with liquidity reducing transactions.