السلام عليكم
http://www.google.com/ads/webmastertools
Set up your account. Click on "Sign up now," and create your new AdWords account.
Log into your AdWords account and follow the step-by-step guide to create your first campaign.
Get your USD$100 credit. In your AdWords account, fill out your "Billing Preferences" under the "Billing" tab. Enter your coupon code exactly as it appears on your mailer. Click "Redeem."