I think for some types of produce, a home garden is an easy win when it comes to cost. Sure there are things that are very difficult (labor intensive, water intensive, etc.) to grow, so avoid those. But tomatoes, cucumbers, lettuce, beans, potatoes, peas, and beans are pretty easy to grow, and seed stock can be purchased cheaply. I haven't done this as an adult because I am so excessively lazy (but it's on my to-do list for this year, finally), but we had a vegetable garden when we were kids, and between my mom, my sister, and I, it was very manageable, and we ended up growing more than we could use, and gave some away to neighbors.