My herb cabinet started with a mason jar of dried lavender I bought at the farmer's market for four dollars. That jar sat on my altar for a year before I really understood what I was working with. I used it in sachets, in offerings, in a sleep pillow I made for my sister who wasn't sleeping well. I watched what happened when I used it and what didn't happen when I didn't, and slowly the relationship grew into something I trusted.
That's the honest way into herb magic: slowly, through experience, one plant at a time. The books that list thirty herbs and all their correspondences are useful references, but the knowledge lives in the relationship. You have to work with lavender β grow it, hold it, smell it, put it in your bath, burn it, dream with it β before you know lavender. Reading about it gives you a map. The plant gives you the territory.
For beginners, I recommend starting with five herbs and knowing them deeply before expanding. My starter five: lavender (calm, protection, sleep, purification), rosemary (memory, clarity, cleansing, loyalty), mugwort (dreams, divination, psychic work, liminal space), chamomile (peace, healing, gentle prosperity), and sage. These five cover a wide range of basic magical needs and are all relatively accessible.
Growing herbs is more meaningful than buying them, if you have any space to do so. Even a small pot on a windowsill changes the relationship. You are caring for the plant through its life cycle; you are present for its growth in a way that picking up a packet at a health food store doesn't give you. When you dry and use herbs you grew yourself, the magical connection is already there β you built it over weeks of watering and watching.
Correspondences β the traditional magical associations of each herb β are useful starting points but should be tested against your own experience. Lavender is widely listed as calming and protective, and in my experience it absolutely is. But I have met practitioners for whom lavender triggers headaches rather than peace, and for them it is not useful regardless of what the books say. Your body's response to an herb is part of your magical relationship with it. Pay attention to that.
Build your cabinet slowly, with intention, and let each new addition come through relationship rather than acquisition. Your herb cabinet will tell the story of your practice more honestly than almost anything else on your altar.