There are only stations in settled space, which is branching out from the areas that we start in. Not sure of the exact distances but lets say 500Ly for example.
Part of the dynamic aspect of the galaxy is meant to be that as people explore and come back and sell the data this may encourage factions to settle further out, thus expanding the area with stations.
If going exploring you will make more /easier money (when you come back and sell the data) if you have the better scanners. I think the advanced will scan a whole system instead of just 500Ls around you so it's easier and the other scanner allows you to scan planets, find an earth like one and it can be big bucks.
A fuel scoop is mandatory if exploring as once you get beyond the settled area it's the only way to refuel, though care must be taken as some stars (brown dwarfs?) don't work with the scope so there is a risk and you have to plan ahead so you don't get stranded.
That said I went for a wander in beta with the basic scanner and just scanned systems as I passed through them and still made ok money, so you don't need to upgrade scanners, it just makes it easier / increases the chance of good payouts.