Do you worry about what your money is possibly funding?
The cocaine trade is notorious for funding dodgy cartels who really fuck over the people actually growing the plant (mind you, the war on drugs fucks them just as much, as they farmers can't grow anything else)
The heroin trade is just as bad.
I personally do have a guilty conscience when buy some items off the road but you can never know for sure where your money is going.
I have to say in all honestly that no not in the slightest, I am more concerned about what our wonderful governments do, they are the biggest terrorist organizations on the planet, look at the destruction the US and it allies has wrought on countries under the pretext of the war on drugs, they spray herbicide on farmers land in some South American countries to try to destroy the coca crop for fucks sake whilst also destroying all the regular food production and poisoning the land and it's people. That worries me a lot more than buying a gram or two on SR irrespective of where my coins end up. The current system creates the paradigm we see today, it is our governments who create the black market for drugs essentially sending billions of dollars into the hands of criminal organizations, it could all be changed tomorrow if there was a will to change the system, stop incarcerating citizens for health issues and promote harm reduction and education. Rant over