Buy ads. Start with a $100 AdWords coupon that is free and not hard to come by. Even $25-50 would be enough depending on your market.
Bid on cheap cheap long tail keywords (3-4 word phrases). You won't get a lot of traffic at first, but that's kind of the point. Get your campaign dialed in where you are making at least $2 per $1 you spend.
Use that money to grow your advertising profitably over time using the same method. Work your way up the ladder so to speak.
You can do this on AdWords, Facebook, Microsoft AdCenter, and probably on AdMob as well. It's not hard at all. It just takes an incredible amount of patience not to blow all your money in a week.
Remember, the goal is profit, not volume. Grow profitably and volume will come with time.
If you can do it in a year, you've won. But if you start with $1 then after one year you have $2, then the next year you have $4, etc. It takes less time if you take a $1000 loan and turn that into $2000. Of course turning $1000 into $2000 is harder than $1 into $2, so take a loan as big as you can still double ;)
In card games or board games, you've created your "engine" -- that isn't victory, but it is a necessary step toward achieving victory.
What I wanted to do, was generate a lot of awareness. When people are aware of your product and see it advertised everywhere, it's more likely they'll check you out. If they happen to check you out after hearing from a friend, it won't even be an ad-referral, and it won't cost you a cent. How do you create awareness without using money?
I have no basis for saying this, and my only proof is a very successful campaign that I ran doing this. Since I've shut my project down, the trade secret isn't very useful anymore. I think there's an innate appeal for certain ads. A lot of ads make it blatantly obvious that they're there, but just doesn't make you want to click. Not because the product looks bad - but I just don't want to click some ads. I know a lot of friends also have this feeling, and a small study I conducted confirmed this.
My strategy was this: Bid minimal amounts after researching bids in certain areas, and create an ad that shoves its name, and possibly basic idea into an user's face. However, do not provide any incentive to click - at all. In fact, make it ugly, but not ugly enough to make your product or service seem bad. This is tricky, and takes some getting used to. The end result is a very LOW conversion rate (usually considered as a failure) - which is exactly what we want. I've gotten a bunch of repeat impressions onto users, without having to pay for them. If they happen to hear about it from a friend, they're now much more likely to check it out, because they're familiar with the name.
I've come up with a bunch of strategies like this, and I really wish I wrote them all down so I could share them. Maybe they're terrible... feel free to tell me it's a terrible idea. It may not work in all business areas, and I'd love to get some feedback.
If you're doing a CPM bid on the content network then you're bidding on impressions anyway, in which case there really isn't a reason to disincentivize clicks.