If you manage Google AdWords ad campaigns for other companies, the logo you receive with the certification has some value. If you are not managing ads for others, it probably has zip value. We have surpassed the requirements for ceritification, but have not yet taken the exam due to lack of time. However, I do plan to take it.
Everyone can apply and I have heared from people that the exam is not that hard, it just takes time. Its reqeurments such as spending 100.000 USD in 3 months, that makes it suspisious to me.
It's $1,000, and that's just to ensure the person is at least somewhat familair with how the AdWords system works. (or just has $1,000 to waste for no good reason)
You are right when it comes to a individueal, but I mean as a company. https://adwords.google.com/support/select/professionals/bin/answer.py?answer=18572&topic=311