To claim your $50 Google Adwords Credit, please follow the instructions below:
1. Sign up a new Google Adwords account by following
this link. (please do not use the same email address as your current existing Google Adwords account, if you have any)
2. When signing up a new Google Adwords account, Googles needs you to enter your Adwords content first before you can sign up. So be sure to have your Adwords content handy. If you do not have anything to advertise yet, just type anything in the title & content, & continue with the sign-up process. Once you have signed up, Google will send you an email to activate your account.
3. Check your email for Google Adwords activation email, then click the account activation’s link given by Google to activate your newly sign-up Adwords account.
4. Now, you have to login & update your billing methods by entering your credit card number. Once you have done that, you will be getting $50 credit immediately in your account (you can use the same credit card as you used in your previous sign-up (if any) of Google Adwords account, there’s no problem at all)
5. To check if you already have $50 credit in your account, go to My Account > Billing Summary, you will notice that you already have a credit of $55 & $5 has been used for "Activation Fee", your left with $50 to use for your new Adwords campaign. Please note that Google will charge the difference to your credit card if your advertising fee has exceeded $50.

$300 Google Adwords Credit or even more…..
The secret is, use the same link again to create 5 more Google Adwords account, you will then have $300 free Google Adwords Credit. What you need is, 5 more email addresses, because each Google Adwords account require 1 email address. You can still use the same credit card of cause, & Google will still give you $50 credit to each your newly created account.
Don’t just stop there, create even more Adwords account….10…or 20…just as many as you want!!! What you need is email addresses. You can actually sign up yahoo mail as many as you want, & use it to create your Google Adwords account for free advertising credit.
Google can be me for this post .. but yes - a bug is always a BUG !!!