how much do you have to pay per click on facebook/google?

[Jake]

Most Adwords ads are between $0.50 and $5.00 a click, it's highly dependant on the competitiveness of a given keyword, some famous Doctor and Lawyer keywords can cost over $50 per click.

Facebook ads don't receive task oriented viewers, rather you are interrupting someone's social meandering, so the conversion rate and CPM cost per impression on Facebook is lower, their PPC costs have been going up and are lower but near Adwords in some cases.

Making a profit was much easier in the early days of 5 cent Adwords clicks, a professional marketer typically has to tune the ad copy, keyword selection and landing page design employing conversion tracking in order to have a profitable campaign.

In some cases, like when doing a "Branding" promotion where getting clicks is not the only goal, paying CPM for impressions can be more cost effective.