Unless, you have acres of land and/or the time, it is not always feasible to grow everything yourself.

But, by getting to know some people you can barter food or get it at a good price.
Trade some extra zucchini for some broccoli or bell peppers.

I know some people that grow and sell potatoes.
For whatever reason, my potatoes never do that great.
I buy from them.

I get my eggs from a guy my husband used to go to school with.
I pay less than the organic ones at the store.
I know where they come from and what they eat.
They are really good eggs.

You might be able to buy a cow or pig for cheaper than buying meat from the market.
You are almost certain to, but all the cost is upfront.
Even after you figure the cost of processing at the locker.
Or maybe chickens too.

If you are not sure where to look, check the free papers you get with all the ads.
If you go to church, ask around.
Check Craigslist.
Do a search on the internet for what you are looking for.