It depends on the topic that your site is about and the ad-placement. Different topics will give you more per click and your ad-placement will determine how many clicks you get.
Their are a LOT of factors which some you can control and others Google controls but I believe bottomline it is the market you choose and how much advertisers are willing to spend to display their ads on your sites, ad placement and the type of Adsense ads you are using. Some pay more than others and if you are running three sets of Adsense ads you can hurt your earnings. Do your research, hone in on higher paying keywords and serve up those ads on your pages that are targeted for the lower cost Adwords. It's a numbers game but there is a science to it IF you want to devote that much time to it. The days of throwing up thousands of pages and earning tons off Adsense are long gone BUT you can still buy cheap clicks and drive them to pages where the ads displayed pay more per click. You need the tools and you need to do the research. hope this helps
For me, it's between 50 and 100 visitors, but a major factor is the niche(s) you're in and the type of site that your Adsense is appearing on.
I get 2000 uniques and make $12/day. So $1 would equate to 166 visitors. Obviously these are my niche specifics. For other sites, prices can range enormously.
my average is around 10000 unique visitors per 100$-120$ site wide year round average with mixed topics across the planet some are much higher some lower if my traffic goes up - $ go up proportinally hence around 100 uniques/day per 1$/day
Wow that is really good. @OP i think it is really hard to guess. It most of the times depend on your niche i would say. Who knows suppose if your keyword value is high you could even earn 3$ within 100 uniques or when your keyword has a low value it may take 300 uniques to just reach 1$.