I'm pretty new to this "game", so here's my first post :)
I read on a Searchenginewatch page that the initial fee for Adwords is $5. However, I can't find anything about it on the Google AdWords pages. In fact, I created a dummy ad and filled in everything (apart from giving billing info) and I never saw anything about this setup fee.
Here [searchenginewatch.com] is the Searchenginewatch page. This obviously makes me wonder if the rest of that page is still up to date.
Your setup fee will be added to your first billing cycle. You will probably be charged $55 -> $50 for clicks received and $5 for the activation fee.