To achieve this, you would have to be able to land a rocket vertically and that is something which is very difficult and the technology to do such a thing has been researched for for a long time without much success which is why this is such an amazing achievement as SpaceX not only did it, but did it with an actual payload of 11 satellites with not much space for extra fuel. The technology required for vertical liftoff and vertical landing should be such that the thrust should be greater than the body's weight and the thrust has to be vectored with some throttling. The base must be capable of calculating the rockets position and altitude with precision as even slight deviations will result in a mission failure. The entire rocket first flies off from the Earth after which the rocket booster seperates from the rocket, takes a U-turn and then comes back to a landing zone a few miles away from its launchpad.
A rocket booster costs roughly about $50 million and you need to build one everytime before you launch a rocket. Now that SpaceX has successfully managed to land it, all it needs is the money for repairs, and refurbishing and fuel which is what will greatly reduce the cost of sending a rocket to space.
This is like a much more amplified version of what Jeff Bezos' Blue Origin did. They took a rocket to the beginning of space and came back. Here they had to take a huge payload, take 11 satellites to their orbits and land a vehicle which is going at a much greater speed than the one which Blue Origin landed. This makes it a historic feat and a day that should be marked in the history of human civilization.
The very fact that Elon Musk actually postponed the launch by a day after reviewing the mission parameters as better weather was predicted and a better chance of a successful landing, 10% higher as he tweeted shows the scale of what SpaceX tried and achieved. According to him, this'll reduce the cost of space travel by a factor of 1/100 which is great
But it's also a big challenge to see if the rocket can actually withstand a second reentry. Escaping from Earth's velocity and successfully reentering would've taken a toll on the rocket's body and it remains to be seen if it has it in itself to do it again.
It's a one small flip for a rocket, but one giant leap for mankind.