Depends on the procedure they ultimately decided to use for the prep. Originally the the shuttle main engines had to be taken apart, with every part inspected before the next launch. If they have to do something like that there's not much point.
But if they can get it to point where it's a matter of gassing it up for the next flight, that's a huge savings. Fuel is a few hundred grand for a rocket that costs sixty million dollars. It's nothing, basically.
Hopefully it won't be anything like the Shuttle. The Shuttle was bleeding edge in a dozen different ways. The engines were extremely high performance and that made them fragile.
SpaceX seems to build things a lot more low-key. They don't use fancy propellants, their engines aren't particularly efficient, and overall they seem to go more for robustness and simplicity.
(Simplicity doesn't really apply for a crazy-ass landing scheme. But aside from that....)
Obviously it remains to be seen, but I think it's likely to be a lot more gas-and-go than the Shuttle.
But if they can get it to point where it's a matter of gassing it up for the next flight, that's a huge savings. Fuel is a few hundred grand for a rocket that costs sixty million dollars. It's nothing, basically.