Really I am amazed how much budgets can vary depending on what you buy and where you buy it. I've read blogs and various stuff from people who live on a whole foods diet cheaply and it is amazing. Most of the stuff I've read is from vegans (since that is the diet I follow), some with very restricted budgets ($20/week per person, etc).
So I thought it'd be nice to share our own tips with eachother
1) My CSA - I just joined one this year. I can't believe already how much food I'm getting each week. For an average of $25/week, I get lots of organic veggies and some fruit.
2) Ethnic (Asian/Indian) markets - Prices are amazing. 20 lb bag of brown rice for $5, large bags of spices for a couple bucks, veggies/fruits very cheap, etc. I can walk out with 4-5 big grocery bags for around $20.
3) Costco. Actually I will say a Costco membership is a bit of a splurge but for me, it is the cheapest auto insurance I could find so I would keep it even if I didn't shop there. There are certain items I buy there that I find cheaper than anywhere else.
4) Trader Joes - Basics usually aren't the cheapest here but for somewhat prepared products, they are cheaper than the average grocery store.
5) Co-ops - I've actually never been to one but I have heard they are great for certain things, like bulk products.
6) Whole Foods - a store I have a love/hate relationship with but they do generally have a good bulk section, they sometimes have a few items on sale that are really good, they have a large amount of (partially) prepared products. Also it fills my occasional veggie sushi urge for cheaper than a japanese restaurant.
7) Grow your own - I have started sprouting which is amazing but I tried my hand at growing veggies last year and it really wasn't what I'd call cost effective but was fun. I don't have a green thumb though.