That is most probably because your site is is a non-pompetitive niche, i.e. advertisers pay low rates per click on relevant keywords.
Maybe you live in a poor country, or your visitors come from a poor country, that's why you get as low for a click. I live in Europe and I get 9 or 10 eurocents /click on a website that has no market in adwords. In western europe (Italy), I get even 40 eurocents/click, and on a website that has visitors from US and Canada I get even 90 eurocents or even more than 1 euro /click. To win big, you need to have a website with visitors that come from rich countries, western europe, US, Canada, Japan and New Zealand/Australia.