I started with 1 BP also now my house is all boas, I can not get enough of them. Just do your research before jumping in to one and if it still sounds good then go for it, just remember they get a bit bigger than a BP but you could pick up a male BCI they stay smaller most of the time.

Price will vary depending on what you want and the breeder, just look around and find what you want. Jimi has some great looking salmons and salmon pastels on his site right now, gorgeous snakes with great color.