Am I more likely to get cancer from sun exposure or from sunblock?

I am not that fair skinned, but I am a moley, freckley kind a gal. Now I hear that most sunblock does not work, or worse, ingredients in the sunblock can lead to cancer. I have stayed out of the sun as much as possible for the last 20 years or so, and I have used sunblock when I know I will be exposed to the sun for long periods of time. Now I don’t know what to do.