Successfully saving money by eating at home does take some planning. I don't plan my meals around what is on sale (which would save me a LOT more money) but I find that too rigid for my taste-buds!
Thoughtful preparation of a weekly menu is critical to success. I use a loose leaf notebook. I make a note of what events occur during the week and make sure my menu takes those in to consideration. If I only have 30 minutes to get the food to the table I need a plan to make that sure to happen. I plan my weekly menus on Saturday or Sunday so I can grocery shop for any "exotic" or fresh ingredients I may need. No last minute runs to the grocery on a busy weeknight! This Dining with Diana post may give you some ideas to help you get into the habit of meal planning http://dining-with-diana.blogspot.com/2010/08/meal-planning.html
Secondly, it is imperative that you have some basic ingredients on had at all times to use to create a home cooked meal. By the time I decide what to prepare, shop and arrive at home I am too exhausted to cook! This prevents that from occurring on a regular basis. My Blog, Dining with Diana ( http://dining-with-diana.blogspot.com/) has some suggestions on how to stock a pantry. http://dining-with-diana.blogspot.com/2010/08/well-stocked-pantry.html
Don't these pictures make it look like my pantry is stocked with nothing but JUNK food?
Lastly, I always have a go to meal in the freezer. It might be a Stouffers frozen pasta meal, a frozen pizza or my meatballs.
If planning a week's worth of menus is too overwhelming for you at first, start by planning 2 days worth of meals. I guarantee the time you save is well worth the effort.
Happy $aving$!
Diana