In 1992, a discussion about buying marijuana was pretty straightforward. Back then, it was illegal and socially stigmatized. Walking into a storefront to buy it was pretty much out of the question — unless you happened to be connecting thru Amsterdam. Most transactions occurred on street corners or back alleys, and payment was in cash.
Four years later, in 1996, the situation regarding marijuana legislatively changed dramatically, when California passed Proposition 215 and legalized marijuana for medical patients. Over the next two decades, 28 states have also legalized marijuana for medical use (apart from a handful of early adopters, the bulk of the medical states have legalized in the last ten years).
And then, in 2012, the situation got even more complicated. Voters in Colorado amended their state constitution with Colorado Amendment 64, which essentially legalized the recreational consumption of marijuana for adults over 21. Seven other states have followed suit within the last five years, including the District of Columbia.
What has not changed is how payments for marijuana transpire.