Regardless of what type of business you are in you have to have a foundation.
For an attorney that foundation is obtaining a law license by passing the bar exam. For a realtor its the real estate license. For just about every profession some sort of license is required.
Without a license that attorney, realtor, etc loses their foundation and is not permitted to practice their profession. Essentially the house they built crumbles to the ground.
Of course you don't need a license to run PPC.
What you need is money!
You need money to run ads on Google and generate leads. Think of this money as a house.
It's safe to assume you don't want this house to catch fire, yet that is exactly what 99% of businesses do!
What do we mean?
Just about everyone starts building their PPC campaigns with arbitrary numbers. In business arbitrary numbers involving hard earned money dont work. Maybe for large corporations that can afford losses but as a small to medium sized business you don't have that luxury.
You have to know where you are to know where your going.
To accomplish this you must understand your Customer Valuation.