Typically it goes something like this (I mention LSD for example only, it is probably pretty much the same for all drugs): Big Supplier either synthesizes grams of LSD, or gets them from somebody who they know IRL who did. Then they -> Sell grams or bibles (hundred packs) on a very exclusive private forum to a vendor who -> Sells ten packs on an exclusive private forum to a vendor who -> Sells sheets on a private forum to a vendor who -> Sells ten strips on SR. each of the higher levels of access is harder to obtain than the lower levels, and the price per sheet grows significantly at each level as well. Funnily enough though, DPR almost certainly makes the most money of everybody involved, despite not even being involved in the supply chain (although he deserves it as he is by far the most exposed target due to operating publicly and being the maintainer of a huge part of the supply chain communications infrastructure).