Gardens are a whole lot more work for a whole lot less results than most people are mentally prepared for.
LOL, yup! And one good hail storm, and BOOM. And don’t get me started about fencing out the rabbits, groundhogs and deer. One rabbit can destroy a decent size garden overnight. They and groundhogs LOVE to nip the stem right at ground level. No fixing that.
There’s a learning curve and some of it is just finding out what works best for your needs, how much room you have, your climate zone, and what you eat.
Some foods are more cost effective to grow yourself. Scallions are an example. They are not cheap but take up very little garden space.
In many places, potatoes are not worth the effort or use of garden space. It depends a lot on the kind of local agriculture you have and how much access you have to farmer’s markets.
One thing that helps tremendously is learning to store and preserve food, especially canning. I use the freezer only for stuff that cannot be effectively or successfully canned.