You certainly don't need to buy anything for this course or in order to begin meditating. I set up this shop in response to the questions I was getting about what items I use and recommend and where to find them. Remember, meditation is not about becoming a "spiritual materialist". When I was a nun I owned only a cup and a wooden bowl and was so happy!
The best barometer for if you should get something is to ask yourself: "Will this inspire me and add depth to my presence practice?" "Is it my mind or my intuition guiding me?" "Is a sense of lack or a sense of love guiding me?"
That said, the following are items that I personally recommend:
Tell me, what will you do with your one wild and precious life? ~ Mary Oliver