“Buying from a reputable manufacturer is crucial, because it matters how the plant is cultivated and processed,” Dr. Maroon says. One clue that a company is cutting corners: too low a cost. Good CBD is pricey—a bottle of high-quality capsules is sold in Cohen’s office for $140. But for many, it’s worth the money. Roth spent $60 on her tiny bottle. But when her energy returned the day she started taking CBD, she decided that was a small price to pay.