Pokemon GO doesn’t exactly like spelling things out clearly. In case you were wondering where to get more of that Stardust stuff, here’s how.
The prime way to get more is by catching Pokemon. With each Pokemon you catch, you’ll get a Stardust and Candy reward. The second way is to keep a Pokemon stationed at a Gym. For each day your Pokemon defends a Gym controlled by your team, you’ll get rewards, including exactly what you seek. You’ll also get a batch when you evolve a Pokemon.
Stardust is primarily used to strengthen Pokemon. You’ll need a sizable chunk of it plus the right Candy to increase the CP of your Pokemon. As long as you keep catching, you should keep a decent supply.