I also have PCOS and IR, btw! We eat almost all whole foods in our house. We didn't really notice a difference in $$ until we added in organic foods. But with the addition of whole foods, we've dropped a lot of fast food, junk foods, convenience foods, (and we also went vegetarian and and tofu and tempeh is way cheaper than meat) and that did help even out the budget. We buy in bulk when we can. Oatmeal, beans, grains, coffee, tea, etc usually come from the bulk dept. We try and buy all vegetables from farmer markets or produce stands.
Hope this helps!