$100 Google Adwords Coupon Giveaway

I'm Approved through Google's Engage for Agencies program to distribute Adwords Coupons to my clients and use in promotion methods in order to attract more clientele. I have decided to give away $100 in Adwords Coupon Credits in a contest. I'm deciding the best way to do it and I'm looking for suggestions. I set up a poll below. Pick an option below or put in your own suggestions.
  *Rules.

1. This is for new Adwords Accounts
   
2. $100 Dollar coupon Expires 14 days after it is awarded
   
3. Coupon will Be e-mailed to the winner 
   
4. Only one coupon awarded