Welcome.
For one thing, we definitely dont't talk about sellers here. Check the
Attitude Page for some important guidance. The only source materials discussed here are live plants and seeds. Growing your own source plant is the best possible route.
What is your native language? There's a chance that you might have source plants growing wild in your area. This we might call the second or third best way. I say third best because bringing a wild plant into cultivation could be considered preferable to simply harvesting it straight from the wild.
If you can tell us the names of any plants you are interested in, in your native language, we may be able help you locate them. There's a fairly well established body of scientific knowledge to be working with. Have a browse around this site and it should already give you some pointers in the right direction.
βThere is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
β Jacques Bergier, quoting Fulcanelli