In a city with dispensaries as common as coffee shops, Denver is undoubtedly the epicenter of the legal marijuana movement. And if you're in the business of bud, it's a good place to be: Colorado accounted for a third of the country's 2.7 billion dollar marijuana market last year.

But with being America's fastest growing industry, comes growing pains. Marijuana is still illegal on the federal level, which has led to conflicting state laws, restrictive regulations, and endless problems for cash-only marijuana business owners and operators.