You can purchase non-organic item's that are safe and for a lot less. Thick skinned items such as lemons, melons, bananas, cucumbers etc... are sprayed with pesticides that can be washed off with soap and water or can be peeled.
It's the soft skinned fruits and veggies that you need to buy organic if you do so. Lettuces, Greens and most of all berries!
Here is a list of the top 12 Organics you should buy from About.com Gourmet Food:
Check it out you will be surprised!
Happy Cooking ;)