how much you will get paid per click depends on the type of ads being served on your page and how much advertisers are paying for that click. sometime your site will display high paying ads and you will get more $$ for those clicks but thats not how you will get paid overall for all clicks.
Yes,it depends on the value of our advertisement.You have to work hard to ensure that only high paying advertisement display in your blog.So that you will earn more money.
Correct me if i'm wrong. What i know is depend on the keyword that your visitor find you. Also placing lesser ads will earn you more.
Lol this is what got from a single square banner on my site ......... yesterday 6 clicks =$.12 today 1 click =$1.89