Card brands do not allow cannabis purchases, debit or credit. The advantage of using CanPay is that it is free for you to use. The ATM fees at the dispensary typically range from $3.50 to $5.00 and your bank may add fees onto that. Those fees can add up. You also don't have change back to deal with. Most consumers are signing up for CanPay to save money, for convenience, and because it is completely touchless.