What trading platform are you using? (And which broker?) If you use a popular brokerage like TDAmeritrade, Scottrade, E-Trade and such, when you enter a "market" order they will send your order to the market maker associated with them.
If you have a Direct Access trading platform, such as RealTick, you can send your order to a particular market maker of your choice, or you can send your order to an ECN. If you send your order to a market maker, there should not be an ECN fee. The market makers make their money through spreads. But since ECNs are supported by their participants, who can be tens of thousands of individuals like yourself or can be market makers, you trade directly with another party without going through a market marker. ECNs charge fees so they can profit.