This may be repetitiveI haven't read the entire thread yet, but these are things that we're doing.
1. Go vegan. Meat and dairy products are expensive. Beans and rice are not.
2. Make as much from scratch as possible. Bread, cookies, tortillas (still working on this one. Mine are too stiff!) Usually much cheaper to make at home.
3. Buy local. Less shipping = lower prices.
4. Buy in bulk. When the supermarket has a good deal on something I use regularly, I buy a case at a time.
5. Menu plan. Fewer impulse purchases = less waste = less $$$ spent.
6. Grow your own. You can eat it fresh from the garden and bottle or freeze the surplus.