Eating Organic?

I have never been a very "green" person, by my own admission, but lately I have heard of so many people in their 30s (ahh, my age group) coming down with a variety of cancers.  Maybe it's just we're more aware, hearing about them more and so many are being detected at earlier ages now?  Whatever it is, I am scared!  I know we can not control how long we are here on this earth, but if there is anything small I can do to try and keep my body healthy as long as possible, I really want to start (hoping it's not way too late). 

Our generation has grown up on so many fast, processed and preserved foods and most of them taste oh so good.  But, in realizing all these individuals at younger ages having cancer, I am apt to change my diet (laden with many preservative-rich foods, fast foods, diet sodas...).

I am researching to find what's best and what's not, because step in to a "health food" or "organic" store and your grocery bill can literally triple if you're not careful.  I'm determined to figure out the most important things to buy organic and local (when possible - like fruits, vegetables, eggs, milk, meats) and then change the extracurricular food choices, too, all the while not budging on my grocery budget.

We have a great store nearby, Native Sun, which houses wonderful items and has a great selection, so I'm looking to spend more time familiarizing myself with items and brands to really get the best things for the money.

I know I am way behind the eight ball on some of this stuff, so if you have any insights, recommendations or other information, please share it!