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."
http://www.perrymarshall.com/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.
David Jackson