Welcome to Gaia! ::

Amazon.com for books because it's cheap and has a wide variety.
Azuregreen for their incenses.
I've used both for years.

I also got my last Tarot deck off of Amazon, brand new for $10. That is hard to beat, it's a lot better than Borders or specialty stores.
While I do agree that you don't need to stock up on books, having a few at your disposal is always a good idea. I have one that is very close to my heart because after a couple of wrong turns on my path my confidence was a little shaken. Although, eventually, I found myself on the right path. At that time I bought a certain book and had found that the journey I was taking followed practically step by step with this book and by the time I got it I was already on Chapter 12. I haven't read past that chapter yet but it was a good boost in confidence.
Besides, depending on you and your deities, some deities like you to do some extra research.