SpaceX's launch prices are already much lower than its competitors. Things will become even more interesting in a few years when SpaceX starts reusing its rockets. Launching stuff to orbit will become so cheap, it's difficult to fully comprehend the impact SpaceX will have. The imagination runs wild. Massive spaceships anyone?
First, there will start to be a lot more people going into space.
Second, there will start to be significant off-Earth infrastructure. Not just satellites, the GPS system, that sort of thing, but meta-infrastructure. Space stations where people do actual work (instead of just research). Systems of transportation. Fuel depots. Repair facilities. Etc. Instead of mounting expeditions to the Moon or Mars or asteroids we will undertake commuter trips. A regularly scheduled vehicle will ferry crew up to an Earth orbit station. There they will travel in a craft that never touches the surface of a planet from that station to another station in orbit of the Moon and they'll take yet another ferry ride down to a lunar colony.
Third, as a consequence of all of this there will start to be a significant effectively permanent off-Earth population and off-Earth economy.
Fourth, as an additional side effect of so much activity significant effort will be spent tackling the medical and other problems of living in space for long periods of time.
And then all of this snowballs until sooner than you realize it there are kids going to college who never knew a time when mankind didn't have cities in orbit, on the Moon, on Mars, etc.
