They promote who they want ONLY, which includes family members, friends and significant others. I don't know anyone who was promoted, within my department, that was given the job based off merit. Instead of picking people fit for the job, they promote and try to mold the individuals into the position.
The job is commission based, and not comparable to other departments.
It's a never ending cycle, if you wind up not wanting to make this job your "career" you will leave money on the table.
Free tickets to Disney, Seaworld, and Busch Gardens