Very hard to answer, anywhere between $0.00 and $10. And it will fluctuate wildly.
It will be determined by many factors, click-through rate and the cost per click of the ads that appear on their site. If I were you I would set the clients expectations very low until you have some data from Adsense that you can use to run more estimates.
Thanks for all the replies. Very helpful. Apologies for the late reply, but we’ve been hectically busy the last few weeks.
To update everyone…
The clients site is now receiving 3000+ visits a day. We implemented adsense for test purposes and they are making around $5-$10 a day. But traffic is growing at an incredible rate and we are now forecasting 10000+ visits a day by 2nd week of September.
So using average numbers they are expecting around $15-$30 a day. Using a lower estimate of $20 X 30 days = $600.
Which won’t make anyone millionaire, but…we are now seriously considering copying the recipe and starting 10 sites in different categories along the same lines. Why? Well $600 x 10 sites = $6000. $6000 x 12 months = $72000. Not bad for some background revenue.
Very hard to estimate. How much any sites makes depends on a number of important factors including topic, content and ad placement.
But if you were to use average figures of $0.50 for Cost-per-clicks (CPCs) and 2% Click-through-rates (CTRs) your clients website would earn something in the region of $10.00 a day and about $300 a month from adsense.
Not much really, but this is just an estimate based on very average values, your clients site could potentially earn much, much more…
As KCgame says, it is tough to generalize. My average for all sites is over $10 per thousand page visits. However, I had two sites with more than 10,000 page views last year (the minimum that I view as statistically significant) that earned less than $1.00 per 1,000 pages due to a combination of relatively low click through rates (CTR) and very low value clicks (nickels and dimes).