You could make it like you can buy more drugs at once from the buymaterials place and you could choose how much drugs would you use at a time. another one is to make login feed like that it show if someone logs in not that someone connects to the server (sorry about bad english )
I will not simplify the drug dealer job by making instant buying for the drugs, but I will make the job a bit more interesting and easier. There is also a lot of things here which will come in the crime pack update. For the idea of choosing the amount of drugs to sell, it'll happen for sure.
The connection feed will be adjusted so it only displays when a player logs in, and will not show discount unless they did in fact log in.