LOL. I did that also while I was working. Don't mind helping anyone out, but it started to become way too much with my schedule. So, when they would come and ask, I would give them the url's or the addr of the local and send them on their way. They are saving a good amt having you do it for them, so at least ask for gas money. You shouldn't actually have to ask, they should offer.
Once they see how much you were really doing for them, I hope they acknowledge it.
Don't make them dependent on you for their supplies. What will they do if/when you aren't there anymore? Go back to smoking?
A couple of times, yeah, it is doable, but they need to independently be responsible for themselves.
Just my 2 cents.