View from the Wing has an extensive post about how you can skip the last segment of a ticketed reservation and potentially save money. It’s a pretty interesting read, although this strategy generally does not work well in the US any more (the carriers have eliminated most ticket pricing quirks these days).
I recommend reading the full post for details, but the gist of doing this is that, sometimes, booking a ticket that terminates in a non-hub city is much cheaper than booking a ticket that terminates in the hub city itself, so if your final destination is the hub city, you can book the cheaper fare that flies through the hub to some other city, but just throw away the last segment to that other city.
There’s a bunch of logistic issues to consider, for example not having any checked luggage and or making sure and making sure your carry-on luggage is either with you on the plane or checked to your intermediate (hub) destination rather than the final, non-hub, destination. Additionally, you have to do this only for the last segment of your flight, otherwise you risk the airline cancelling the rest of your itinerary.
To be honest, when I’ve run across this concept, it has resulted poorly for the person/people involved. The cases I’ve heard are where people have a round trip ticket to a certain destination, but they decide to skip one of the legs on the way to their destination and take alternate transport to the destination. Since you’ve “missed” one of the flights in the itinerary, the airline takes the liberty of cancelling the rest of your trip. Which usually results in some last minute scrambling as well as expenditure to book a return ticket home! Be careful about skipping legs of your itinerary! If you’re doing it for convenience or because you have alternate transportation to replace a leg, definitely check with the airline to see if it is ok with them so that they do not cancel your entire itinerary…however if you’re intentionally throwing away a ticket at the end of your trip, then there isn’t as much a need to talk to the airline.