Returning to the idea of cooking and freezing food, another simple way to get started at this is to cook double. Making a favorite dish? If it's something that may freeze well, it's often hardly more work to cook twice as much at a time, and the extra half can be frozen for a quick future meal. The savings here is mostly in efficiency, of time and energy, but this is an approach that can also allow singles and couples to take advantage of the lower costs of bulk purchases.
Want to make breakfast tacos, but the one pound chub of ground sausage or turkey is way too much? Go ahead and cook up the full amount, then fill the tortillas and roll up (omitting sour cream or salsa for now). Let them cool while you have breakfast, then use ziplock-type bags to package them up in single meal portions. Then when you think you'll want a filling, hot breakfast, pull a package out of the freezer at night to thaw overnight in the refrigerator. In the morning, warm them in the microwave for a quick hot breakfast. If you like sour cream (I substitute plain yogurt) or salsa, spoon a little out onto your plate and dip the breakfast taco. For a larger family, you can still cook up large batches of the filling and make them up on the weekend (and involve the kids in a filling-and-rolling party).
If you have a favorite casserole that you think might freeze well, this can work. If it makes way too much, just make the normal recipe and divide the leftovers into single meal portions to freeze. If you have a larger family that this casserole feeds perfectly, fix two at once, take one out of the oven slightly early, and freeze. Rewarm in the oven (which should finish cooking it too). Some quiches freeze well too. Keep in mind that sour cream and yogurt and cream based sauces don't always freeze well.
A single or couple eyeing those family packs of steaks or ground beef? Go ahead and buy them and cook the whole batch at once. Freeze the extra in single meal portions. If you're using a grill, cooking a lot at once makes the most efficient use of it.
One of the tricks to this approach is remembering to pull items down to thaw in the refrigerator the night before (for breakfast) or the morning of (for supper). I usually leave frozen lunches in the freezer until I'm about to walk out the door because of the drive and delays when I get to work in getting items in the refrigerator. I find I like the texture of food that's been thawed naturally a little more, and it cuts down on microwave time.