From AP
As part of a small-business network Visa designed for Facebook, the world’s largest credit and debit card processor is paying for $2 million of advertising on the socializing site. Visa also will promote the new Facebook service in a multimedia marketing campaign beginning next month.
Visa is giving a $100 advertising credit on Facebook to each of the first 20,000 U.S. businesses that download the Web application needed to join the network, which debuts Tuesday. About 80,000 small businesses already have profiles on Facebook
How to get your free $100 Facebook Counpon? All you need to do is have a Facebook account and add the Visa Business Application. You will then receive an email shortly after with a coupon code. It will have instructions on how to redeem it.
Here’s more details what you do to get $100 in free Facebook Ads:
1. Add the Visa Business Network Facebook application to your account. This application is focused on helping business owners meet each other and network.
2. Complete the Visa Business Network process to register the application.
3. Check for an email from the Facebook Ads Team with the subject “Facebook Ads Alert: Coupon Code Assigned.”
4. Get your coupon code in this email. It is something like this “Your coupon code is: 1111-2222-3333-4444″
5. Add the coupon code to your Facebook Ads account
6. Create your ad and use the coupon
That’s all 
P/s: As they said that the first 20,000 business owners to sign up will get a coupon, I have just tested and it’s still available.
Dear Ng:
Thank you for joining the Visa Business Network! To help you grow your business,
we’re giving you a $100 coupon good towards Facebook advertising credit. Your
coupon must be redeemed and used by 10/31/2008.Your coupon code is: xxxx-xxxx-xxxx-xxxx
If this is your first time advertising with us, you can create your first ad and redeem your coupon at:
http://www.facebook.com/ads/create/?coupon=xxxx-xxxx-xxxx-xxxxIf you are a returning advertiser, you can redeem your coupon by the following:
1. Log into your Facebook Ads account at http://www.facebook.com/ads/manage/?act=xxxxxx
2. Click on the “Billing” at the top of the Ads Manager.
3. Click on the “Funding Sources” tab on the Billing Summary page.
4. Click on “Enter Coupon Code” and enter your code as shown above.Thanks for joining The Visa Business Network!
Sincerely,
The Facebook Ads Team
PROMOTIONAL TERMS: The promotional coupon code and the advertising credits are valid only for purchase of advertising through Facebook’s online advertising system. May only be redeemed by Facebook users who add the Visa Application. Advertisers will be charged for advertising that exceeds the promotional credit. Advertisers will need to suspend their ads if they do not wish to receive additional charges beyond the free credit amount. Subject to ad approval, valid registration and acceptance of the generally applicable Facebook Advertising Terms and Conditions. The promotional coupon code and advertising credits are non-transferable and may not be sold or bartered. Offer may be revoked at any time for any reason by Facebook. One promotional coupon code per individual. Promotional coupon code equals $100.00 USD which can be applied to the purchase of advertising through Facebook’s online advertising system. Offer valid only for sign ups using the coupon code or URL link received upon adding the Visa Application. Expires 90 days from date the Visa Application is added to the Facebook account.