When I start a PPC campaign I include keywords that I hope will target the right people, I write multiple ads that I hope will attract clicks, and I make landing pages that I hope will convert.
As the campaign runs I am able to eliminate keywords that do not convert, eliminate ads that don't attract clicks and eliminate or modify landing pages that do not convert. Every time you eliminate something the performance of your campaign should improve - if you made a wise decision. Your profit should improve and your quality score should improve and that can bring your bid prices down - if you know what you are doing.
It is something like sighting-in a gun. You shoot, see where you hit, adjust the sights, shoot again, and keep at it until the gun is zeroed in.
If your campaign is targeting a niche with vigorous activity you will get lots of data quickly. But if your campaign targets a sleepy little niche with very few searchers, it can take weeks or months to accumulate enough data to eliminate poorly performing keywords, ads, landing pages, etc.
Making money on PPC can be very difficult. You can be competing with people who can obtain product at cut rate prices, ship their packages at a discount and have highly efficient fulfillment teams and very smart ad managers. If you are not tracking your conversion rate and keeping a close eye on your profits and costs you can loose more money than you make at PPC. I am willing to bet that a lot of my competitors are loosing money at PPC and don't know it.
It is really hard for a small business to make money at PPC. You have to be super smart and super efficent and get all of your expenses down to rock bottom. Try it and find out. I bet you are surprised at how easy it is to blow a lot of money.