To schedule an appointment, your artist will take a non-refundable deposit. This goes toward the cost of the tattoo. Please inquire with your artist regarding their own deposit policy, but typically the following rules are true:
You can pay your deposit by cash or card.
The deposit is strictly non refundable, but is good for up to 2 reschedules with at least 48 hours notice.
Anything outside of that it's no problem to reschedule, it will just require a new deposit.