San Antonio tattoo parlors may be participating in the practice of offering deals on Friday the 13th next week. Tattoo parlors usually have a pre-made list of flash tattoos for patrons to choose from for 13-dollars. Some shops require a minimum seven-dollar tip, and others charge a service fee. Some tattoo shops extend the special for the entire Friday the 13th weekend, and others start several days early. Rules vary from one parlor to the next, so phone ahead.