Laura, The way it is around here is that we give freely. We commonly give, trade, or for the price of shipping (SASE) send seed. If I were in your shoes, don't worry about accepting what is offered. It is from the goodness in their hearts and the desire to help out. Find that anywhere else.
I have been growing for decades, and I got my start from the genorousity of early CP people, and money was not an issue. Still isn't. So please, don't make it one. Accept our generousity, and grow girl, grow! P grandiflora hibernacula can take the nasty winters of the north, so get them now. And build a frame out of 1" x 2" wood, and cover the whole thing with bird netting. It works for me, and even the dogs and cats around here cannot get to my plants. (Those pesky starlings have to go somewhere else for lunch!!) I can walk around inside the frame and love my plants, but nothing else can get in ('cept slugs and snails), not even the squirrels and the cats. It works. Its cheap. It saves plant lives!!!!