If you are not already from the meth world, it is best to not add that to your life. She, her contacts/friends, all of it. It is a security problem in more than one way. Others in leadership positions that are aware of the area will judge you as one of them.
You do not sound like a cold-blooded greedy without shame sort of dude. Because of being a decent guy, you should avoid this, leave it for those that are like that. Unless you really want to become that. If so, by all means, full speed ahead. Who she buys from will have a long list of other women that are just like her and probably younger and better looking. They all are available to your wallet. The man will even send them to you if he knows your providing for them to pay him.
No disrespect intended, by maybe you have no idea about this... hunt elswhere.