On the internet with a search engine, on a map, etc. Or ask friends / family, actually.

That's what I do when I need something I don't know where to find. Before the internet you had the yellow pages, I guess, and word of mouth.

In any case, I'm pretty sure I never ever ever heard or saw an ad that made be discover something I was interested in.

I don't want to allocate any time during which I passively listen or watch ads in the hope it will lead to some epiphany.