In Australia a small bunch of herbs at the supermarket is approximately $3. A good brand of mint tea can cost $8 for 125g. And a small bunch of silverbeet can cost $4.
Therefore we recommend you Beat the Man and grow some of your own herbs and vegetables. As this video shows, you do not need a large plot to help you save at the supermarket checkout.
It also demonstrates that growing some of your own produce does not have to be time-consuming. Keep it small and manageable if you are busy doing other things. And a smart idea is to swap your produce or barter something else with others in order to get what you might not grow yourself.