Ask HN: What free/paid app marketing strategy has worked best?

I've tried Facebook ads, Google Adwords Install ads, Fiverr gigs, etc.

It seems almost impossible to post on communities without being annoying. I would write a blog post, but without any regular subscribers, my posts won't be read at all.

I wouldn't mind spending money for REAL users, but it seems hard to get quality users.

Regardless of the type of apps, what has worked the best for your app?