You won't know if it is worth it until you do it - no promises, no guarantees.

If you have something people want - they will buy it. If you are promoting "buy my stuff because I want money" they probably won't.

I don't mess with ads, such as here, I focus on targeted CPC ads for google or facebook, but that is my recommendation to get your targeted traffic.

I'd also be interested in knowing how much success people have had with them.

But then again.. the results would vary depending on the ad and the product.

There are no averages. It depends on the ad, the headline, the actual offer. People think that because they're here in the greatest IM show on earth that there's just money floating through the air, easy for anyone to pluck a few thousand by just putting up an ad. Not true.

I see banner ads all the time that absolutely suck. They're awful. Better those people took their money and took their families out to dinner.

Good offers (stuff that appeals to people on this forum) with good ads will bring good results. That's the best answer without actually knowing what you're trying to accomplish. Good luck.