Oh yes, most definitely! In fact, I only buy baby food to keep in the diaper bag for emergencies or going out to eat.
I usually make up a big batch of food at a time. I'll cook a whole bunch of spinach, for example. I cook it until it's very soft, then blend it till smooth. I add in extra cooking water to thin it out if necessary. Then I pour the blended spinach into ice cube trays. I freeze it until it's frozen, then store the individual cubes in a freezer bag. Label it well!
You can use rice flour to make rice cereal, although the store-bought rice cereal is fortified with extra iron and vitamins.
Here is a website which I really enjoy: http://www.homemade-baby-food-recipes.com/ It gives ideas for baby foods that don't come in jars (such as melons, avocados, and quinoa), plus guidelines for introducing new foods to babies.