Looking for helpful suggestions/ideas on how to be self sufficient in a small apartment with no yard or garden area.

Groceries are becoming more and more expensive, and before this week, my SO and I were already getting only the necessities when at the store. Do any of you have any suggestions/ideas on how to be self-sufficient when we have no room to grow a garden and have limited space indoors to grow anything?

Edit: Thank you all so much for your advice! I am still doing some research, and I will most likely do a few of the things you suggested.