What Google Says:
Advertise with Google AdWords ads in the Sponsored Links section next to search results to boost website traffic and sales. With Google AdWords pay-per-click (PPC) keyword advertising, you only pay for results. AdWords is an essential online marketing solution for any website owner and any type of business.
Source: Google Adwords
Why You Should Use It:
You only pay for people who actually click on your ads, so you’re only paying for results. Plus, you have access to fantastic analytics to be able to see everything about who clicked on the ads.
For the Google Adwords account itself, there’s no minimums, you have total control over when and where the ads run, and you can cancel the account at any time.
You can also do very precise targeting of where the ad will appear making it a great choice for local businesses. Your ads can also be targeted to YouTube and Gmail for even wider coverage.