Mandy3206:This is an easy question:
1) Train yourself.
2) Log at least 50 dives in rental or borrowed gear to get experience.
3) Buy the BP/W setup if you still want it.
I'm very happy with mine, but I bought it after 300+ dives, when I was really sure what I wanted and did the apropiate research for the gear I wanted.
Welcome to the sport and buy only quality gear, avoid the cheapo stuff, you may end up spending more in the long run.
Mandy, I respectfully disagree. I think most new divers will get weary of paying the rental charges long before they get to 50 dives, and I don't know where I could rent a BP/W if I wanted to do so. There are also issues with varying quality [or lack thereof] and fit with rental gear. The new diver I dove with last weekend had a rental BC that was pretty new and of good quality -- actually about the nicest rental gear I've seen -- but he and that vest BC just did not get along, and he was having issues with it throughout the dive, which was a freshwater practice dive in about 3 - 5 feet of visibility. Someone of more modest means than he would have more painfully felt the pinch of all those rental charges to do a practice dive in 3 - 5 feet of visibility in equipment they were struggling with.
Personally, I went the BP/W route right off the bat and am happy with that decision. If I'd decided to get a different BC and later ended up thinking that it was a mistake that needed to go on e-bay, I still think I'd be better off than paying rental charges for 50 dives. All those rental fees add up. If uncertainty, confusion, and the expense of what the diver thinks he/she really wants is holding back a purchase decision, it's always an option to get something on e-bay, get diving, and put whatever it is back on e-bay when the diver is comfortable enough with the purchase decision to put the money down.