The suppliers arrive at one of the nation’s largest marijuana dispensaries carrying hundreds of pounds of cannabis in duffel bags, knapsacks and baby diaper totes. They leave with those same carriers stuffed with wads of cash.

Harborside Health collects the money from thousands of customers, spending $40 to $60 a pop for one-eighth of an ounce of pot. No credit cards or checks are accepted.

That’s not by choice. Though Harborside’s business is legal in California and a growing number of other states, most banks still won’t touch the marijuana industry, fearing the federal prohibition that remains in place.

Read more: Shunned by banks, legitimate pot shops must deal in risky cash | LA Times.