I found a great supplier for all kinds of dried herbs and herb powders on e-bay. They are wildcrafted and she only charges one shipping rate regardless of how much you order.
http://www.atlanticspice.com/ I buy from here all the time. They have 3 different grades of lavender buds, If you can see them i would go with the first grade.... if you cant... the cheapest will do. A lb is a lot of lavender, I keep the extra in a large canning jar to keep the scent in.