I've done bootcamps in the past, and although many balked at the idea initially, my 5:45am group had almost 20 women in it! Come to think of it, the early mornings seemed to work for more women...before this run, I did 5:30am but realized that I wanted 15 extra minutes of sleep
The last bootcamp I did, which was tied with the last gym I trained at, was held at 7:30pm. I had a group of 11 women that time. I would have preferred to do it a bit earlier, say 6:30, but the aerobics room wasn't free until 7:30. Damn those hip-hop classes! :p
I prefer early morning. As much as it can suck now and then, you'll have fewer drop-outs. I am a morning person so it's all good. I think mornings are the way to go b/c it's easier to make excuses and skip as the day goes on. If you make them do it first thing in the morning, they have no reason not to.
Also, I think 3 times a week is more beneficial for them...they'll get better results...BUT...if you're holding an evening class and you try to do MWF, that's gonna be tricky. Of course, you could do MWTh or however you want to lay it out.
I charged $250 for a 4 week bootcamp at the gym (they took HALF the profits, ugh)...and then when I did bootcamps on my own, I charged $200-250, depending on how many days per week.