The same applies to acrobatics. Such a person can show you what the judges are looking for in competition and can tailor a course to meet your individual needs. The syllabus of instruction is also important and should be reviewed with you. Generally, a school with an established curriculum or flight syllabus is the mark of a good organization and the likelihood of their providing good instruction is much greater. The FAA has no regulation concerning required course content of acrobatic schools nor is such a regulation proposed in the foreseeable future.
Cost varies considerably depending on type aircraft used and the instructor's background.
In summary, check out the school, the equipment, and the instructor thoroughly to assure they fit your needs. FAR Part 23 prescribes airworthiness standards for normal, utility, and acrobatic aircraft. This does not mean that all acrobatic maneuvers can be flown. Operating limitations must be observed. In many cases, operating limitations did not preclude the performance of certain acrobatic maneuvers.