Over the last few years pay-per-click advertising has gotten increasingly more competitive and much more expensive.
The days of paying 10 cents for a prime keyword are long gone.
Nowadays, ppc requires a substantial investment. And if you don't know what you're doing you can lose a ton of money.
In that regard, before you enter the ppc arena, I suggest you take time to study the ppc market and learn how to make it work to your advantage with Perry Marshall's "Definitive Guide to Google Adwords."
If you're serious about ppc advertising, I consider it a worthwhile investment.
And just for the record, I don't make a dime if you purchase the book. This is just another fundamental marketing tip.