I am running a campaign for branding purpose so I Choose display medium and used CPM bidding strategie. But adwords is still charging me for the click in that particular campaign. As far as I know under the CPM bidding strategie advertisier pay onlye for the impression but not for the clicks. and the clikes are much more expensive in comparison to search network campaign.
If your campaign is set for CPM bidding , google will charge you for impressions. You can see this also in the Billing tab.
What could be confusing is the fact that AdWords will also "calculate" the "average CPC" but this is just a calculation , it is not the measurement for what you pay.
For example if you bid 1$ per 1000 impressions and you get 10 clicks after 10.000 impressions and 10 $ spend, then AdWords will calculate that a click is evaluated at 1$ by dividing the total amount you have spent for impressions by the total no. of clicks.
In the same way, when you bid for CPC , you can activate the column avg. CPM and AdWords will show you again a calculation : total amount spent for clicks divided by the total number of impressions, even if you do not pay by impressions.