This is kinda like part 1, but I wanted to emphasize the awesomeness of cooking a whole chicken. Per pound, a whole chicken costs next to nothing (unless you go to Martin's where everything is expensive). Recently, I have also found split chicken breasts on sale for 88 or 99 cents/lb. and they work great in the slow cooker too.
When I cook a whole chicken, it takes a few hours on low. You can add spices like garlic or whatever you like. Once it is tender and the bones come right out, you just remove it from the crockpot and chunk or shred the meat. I discard the skin and bones (or if you're especially resourceful you can make broth with those) and use plastic containers to freeze it. Then the possibilities are endless!
-Casseroles of any kind
-Anything you would use pre-packaged diced chicken to make for a much lower cost.