Again - weird - I was just thinking of this the other day.
At a full-service wash, I'm guessing the overhead would be crazy. I was a manager at a car wash like that in gainesville FL for a couple years. IIRC, boss man told me the equipment was $1mil. Plus, we had 6 - 10 employees vacuuming, cleaning windows, cleaning interior, drying, etc. Plus, if I had to guess, the liability insurance would be pricey...especially after you roll the first car into the reclaim pond (happened once while I was there.) So yeah, overhead.
Like others have said, though, at the right location, one should be able to pull in some decent coin. Washes ranged from $5 to $25. I'd guess our average ticket was $10. On a REALLY busy summer day, we'd roll 300 cars...which is why this seems physically impossible:
JFX001 wrote:
I worked at one in MI while I was in college. One guy to take the money, 2 to do the rinse/pre-soak and send them through and 2 to dry with towels at the end.
Winter was suckage, weekends had 120-130 cars per hour. Minimum wash was $4.95. You split the tips.
Anyway, that's $3k/day on the busy days. Probably $500-$600 in labor. Not sure what the chemicals cost per day or the vacuums cost to run.
Cleaning the pit ain't so bad. I did it every week; as there was a 10 dollar bonus for whoever did it, and everyone else was too lazy/pussified to get dirty. I also stayed late on Saturdays and dug through the vacuum bags. That was usually an extra $7-$10 for a half-hour of dirty work. 
