Does anyone run ads successfully?

Over the last 10 years, I kept trying to run various ad campaigns for my products. NEVER was I able to get any sale from ads, and it seems like all traffic is bot traffic.

I am not sure if I'm doing anything wrong, or maybe my budgets are too low (<$50/day), but runnings ads always seemed like simply burning money to me.

Are there any tricks I'm missing to actually get sales and good traffic from ads? I tried even very niche targeting (only high-paying countries, very specific keywords, etc.), but very rarely I managed to get any human-looking visitor.