They pass the rest of the commission on as a reduction in price. A common rule of thumb is about two cents a mile. There are several variations on the consolidator theme. Discount agencies buy from the consolidator and there is a markup for their service. They can be useful if you re in a rush and need the agency to shop for you.
Wholesalers buy from the consolidators and sell to the agencies.
There's an extra markup. They look for a ticket for you and may require a deposit in advance to do the looking. Especially for long flights or offbeat destinations, this can work wonders. But if the savings are relatively modest, then you must decide if convenience is worth the extra price. Consider charter airlines Charter companies hire airplanes and fill them to the brim.