I know it takes time to build up these kind of passive income
businesses.
But if you tell me I can get only a few bucks a month, what's
the point?
What is the opportunity costs? 
Bear in mind it's the holidays 
And I started the program midway through september.
A few dollars a month is enough for a few cups of coffee.
Adsense income depends on the following:
Traffic * Click Through Rate * Payment per click
Till now, I have just below 9k page impressions only... My
target is to reach that amount daily by next year... That should
reach >300 usd monthly :D
But I will be happy even with $50 a month...
I'm still building on my traffic. :D
And that site has many other purposes as well; adsense is only
part of it...