I've had everything from 0.01 to about $15ish. But longterm average is about 20c a click. Also I hate December, my traffic is down 70% from normal across the board, earnings down almost as much
Topic of your blog is important to get highest per click rate. you should have a niche focused with similar articles that have high click rate. there exisits some niches which have more than$20 click rate.
Its December, every December my traffic takes a massive hit. I just don't have any Christmassy stuff on my site. I'm barely going to hit $200 this month, no surprises there. I get my traffic from search engines, and that particular site I don't actually promote at all, never have.
Most of my sites have average around $0.80/click but some are closer to $5. All depends on which have more advertisers. I actually put together a full list of top paying keywords and have niche specific lists. See my sig for link if you wanna check em out.