alt Hacker NewsWhich ad network do you use? Google, Meta, TikTok? I imagine you had pre-existing experience especially if it's Google, it's rare to get good RoI out of it unless you really know what you're doing. If you go with the defaults you'll get a few thousand "clicks", zero actual users among them.
Google and Meta. I did work for a Marketing agency for years handling automations development for them. So I have been exposed to hundreds of campaigns across different industries and have seen what works well and what doesn't. Not saying that you need this experience, but once you see stable results from others; and how to protect them, its hard not to chase after them as well!