This is an interesting subject and one I've been pondering myself for a while as I've always wanted to get certfied to become a personal trainer (in fact I've had my study materials for over 7 years now... just haven't had the time or ambition to study and take the test). A couple of things that I've seen work....
Option 1: My previous trainer has her gym set up in a small garage/shop type building. She has a squat rack, bench press, bench that inclines/declines.. plus a bunch of dumbells, a few exercise balls, a few bars for different lifts, exercise bands, a nice treadmill (like one you'd find in a gym, not a cheap one made for home workouts), a nice elliptical (Id say a good one of these costs about $3000-$4000... probably same with treadmill). She has rubber mats on the floor and mirrors along every wall. She said the total cost to get the gym set up was $17000 (if I remember correctly). She is leasing the shop from her brother and pays $500 per month rent... this cost could be cut if a person actually had the shop built on their property instead of on somebody elses land, but then you'd of course have to have the proper location.
Option 2: Prior to moving I was working at a small, privately owned gym. The gym owner and i were very good friends and he pretty much ran the whole gym by himself and I worked for him teaching classes. We discussed me getting certified as a personal trainer so i could help a bit more. He was going to let me name my price to clients and he was going to charge me 30% of what I made from clients. Soooo if I charged $50 per hour, I would take home $35 and he got $15. He would also obviously benefit because those clients coming to let me train them would have to have gym memberships.. which he got the money for. The benfit of having a studio type gym is that clients don't have to pay for a membership.. they simply pay a set fee per session... however most people will still need/want a gym membership so they can exercise on their own outside of our training sessions.
As for "selling" to clients and getting them to hire YOU as your trainer... I honestly think the number one marketing tool that personal trainers have is their own body. Probably one of the most important things (in my opinion) that a person can do to keep people flowing through their door is to keep their body in tip top shape. One of the big reasons that I decided to compete in the upcoming figure competition that i've been training for is because after graduating college I decided to get serious about getting certified as a personal trainer and I really wanted to get my body to the next level of fitness before doing the personal trainer thing. (Although now that i'm training for this show i have absolutely no time or energy to study... so the personal trainer thing has taken a back seat to the figure competition). A few things that I've noticed since I started training for this show 1) My spinning class has GROWN... Now I'm not sure if this is a coincidence or if people think that I've actually lost all this weight because of my killer spin class but my class has grown (I hope people don't think this... spinnning is great but its definitely NOT the best way to get a tight bod) 2) I've had more people approach me at the gym asking me what I'm doing to get in such great shape... If I was a certified personal trainer, these encounters would be great opportunities to offer to train people to get them into great shape as well.
Of course, I think things like honesty, integrity, and a bubbly/professional personality also help to draw clients.. However I think one of the major things is having potential clients see you and think "damn, I want a body like YOU! Train me and show me how I can get into such great shape!".
Just my thoughts.
Cassie