So many good replies here! Another way to eat more cheaply is to plan your meals. I make a plan for all the weeks meals before I shop, which stops me from buying fresh produce that I'm just not going to use. I just read that Americans are throwing out about 40% of the produce they buy. Planning meals should help reduce that number.
I read Cheap Healthy Good - Frugal Recipes and Food Tips
regularly too for ways to eat well, inexpensively.